I was looking at the Shadow monster and it says that everytime it hits a player, it reduces their strength score in 1d4. Does that score reduction change the player's strength modifier?
I was looking at the Shadow monster and it says that everytime it hits a player, it reduces their strength score in 1d4. Does that score reduction change the player's strength modifier?
Ability score modifiers are based on the current value of the ability score, so if the ability score changes, the modifier may change.
In some cases it might not, just because multiple ability score values can have the same modifier — for instance, if your Strength is 17 and you roll a 1 on that d4, your Strength will go down to 16, but the modifier will remain +3, because that's the modifier for both 16 and 17.
Worth pointing out, since it's a thing people often ask about this, that in the 5.5e rules finishing a Long Rest resets any active ability score reductions.
If I have a magic item that gives me a 19 strength, what strength do I lose?
Using the -1 example.
If I have a 10 ability and the magic item. Does my ability drop to 9, but my strength stays at 19 due to magic?
If you have a magic item that sets your ability score to a specific number while you're using it, reductions (or increases) to your natural ability score don't have any effect on that. So in your example, your Strength would still be 19 while you're using the item, but if you took off or deactivated the item, your Strength would be 9.
That depends on how that item is giving you the 19. I assume that it's because it "sets" the score to 19, and so you wouldn't lose str. However, you'd still need to track it just in case you lost the item before taking your long rest and resetting the reduction.
If I have a magic item that gives me a 19 strength, what strength do I lose?
Using the -1 example.
If I have a 10 ability and the magic item. Does my ability drop to 9, but my strength stays at 19 due to magic?
If you have a magic item that sets your ability score to a specific number while you're using it, reductions (or increases) to your natural ability score don't have any effect on that. So in your example, your Strength would still be 19 while you're using the item, but if you took off or deactivated the item, your Strength would be 9.
Could you say where that ruling comes from?
From what I could tell, if you're using a magic item like the Belt of Giant Strength, it simply replaces your Strength Score while you are wearing it. "While wearing this belt, your Strength score changes to a score granted by the belt."
The Shadow's ability says "Draining Swipe. Melee Attack Roll:+4, reach 5 ft. Hit: 5 (1d6 + 2) Necrotic damage, and the target’s Strength score [emphasis mine] decreases by 1d4." If the target's strength score was 21 (we'll say it's the Belt of Hill Giant Strength to be specific), then their natural score is completely replaced by the belt's, so it would be 21. That 21 should then be reduced by 1d4, right? Nothing about the belt says "this score cannot be reduced", it is just the new Strength Score. I can see tracking the negative to Strength in case they took off the belt (they have -6 to Strength Score because of the Shadow's attacks, and if their "natural" score is 10, when they take the belt off their score becomes 4), but I don't know why the score granted by the belt would be unable to be affected by other things.
If I have a magic item that gives me a 19 strength, what strength do I lose?
Using the -1 example.
If I have a 10 ability and the magic item. Does my ability drop to 9, but my strength stays at 19 due to magic?
If you have a magic item that sets your ability score to a specific number while you're using it, reductions (or increases) to your natural ability score don't have any effect on that. So in your example, your Strength would still be 19 while you're using the item, but if you took off or deactivated the item, your Strength would be 9.
Could you say where that ruling comes from?
From what I could tell, if you're using a magic item like the Belt of Giant Strength, it simply replaces your Strength Score while you are wearing it. "While wearing this belt, your Strength score changes to a score granted by the belt."
Right. That's what it says. While wearing the belt, your Strength score is 21 (or whatever). So while you have the belt on your Strength score is 21, regardless of anything else.
Consider also that even if it didn't work that way, all you'd have to do is take the belt off and put it on again to get your 21 Strength back.
Is it replaced or is it boosted by the belt? Logically it made sense when I asked, that it boosted ones strength which is why you have a flat rate/number and it was not relevant what your actual ability score is.
If I have a magic item that gives me a 19 strength, what strength do I lose?
Using the -1 example.
If I have a 10 ability and the magic item. Does my ability drop to 9, but my strength stays at 19 due to magic?
If you have a magic item that sets your ability score to a specific number while you're using it, reductions (or increases) to your natural ability score don't have any effect on that. So in your example, your Strength would still be 19 while you're using the item, but if you took off or deactivated the item, your Strength would be 9.
Could you say where that ruling comes from?
From what I could tell, if you're using a magic item like the Belt of Giant Strength, it simply replaces your Strength Score while you are wearing it. "While wearing this belt, your Strength score changes to a score granted by the belt."
Right. That's what it says. While wearing the belt, your Strength score is 21 (or whatever). So while you have the belt on your Strength score is 21, regardless of anything else.
Consider also that even if it didn't work that way, all you'd have to do is take the belt off and put it on again to get your 21 Strength back.
I get that line of thinking, I just can't help but feel like it leans on assumptions that aren't stated anywhere. I did a bit more research and it seems Jeremy Crawford did state that your "natural" score is affected by things like the Shadow's attack, but not those granted by a magic item. So my viewpoint is obviously not shared by the designers. But it DOES feel like something that is more of a "we intended it to be this way, even though we didn't write the rules like that." My best example of that is the Twinned Spell rules in 5e, where they added language later (not an errata, as far as I know, but a "suggestion on how to rule if a spell can be Twinned or not") so that a spell like Dragon's Breath couldn't be Twinned, while as written is was a perfectly acceptable candidate for Twinned Spell.
My reasoning for this is that there isn't a real difference between the Strength Score granted by your class/species/feats and the one granted by the Magic Item. The magic item says it doesn't have an effect if your strength would be equal to or greater than what the magic items sets it to. So the magic item isn't magically forcing a certain number on the character. If that were the case, even if their strength naturally was a 26, the Belt would change it to a 21 because it is magically setting a score. Instead it seems like it is enhancing the strength of the character.
You Strength Score is a set number. It is set by a combination of feats, abilities, species, class, etc. The Belt (in this example) simply gives a new place from which to get that number. I concede that Jeremy Crawford says that number cannot be changed by anything, but that just seems off to me. Nowhere I can find in the rules does it talk about "your natural Strength score" or give any indication that you have two different Strength Scores (or any ability score) at the same time. It all just seems like "this is how we wanted it to work, but we didn't bother writing that into the rules."
So I'm wrong per the developer, but I don't think my reasoning is wrong.
I was looking at the Shadow monster and it says that everytime it hits a player, it reduces their strength score in 1d4. Does that score reduction change the player's strength modifier?
Ability score modifiers are based on the current value of the ability score, so if the ability score changes, the modifier may change.
In some cases it might not, just because multiple ability score values can have the same modifier — for instance, if your Strength is 17 and you roll a 1 on that d4, your Strength will go down to 16, but the modifier will remain +3, because that's the modifier for both 16 and 17.
Worth pointing out, since it's a thing people often ask about this, that in the 5.5e rules finishing a Long Rest resets any active ability score reductions.
The difference is that there is no language in the Class/Abilities portion of character creation that says anything to the effect of, "While you are a character in this game, your [STR] score is X." The belts of giant strength do say this, however. And that's why a penalty does nothing while wearing it.
The difference is that there is no language in the Class/Abilities portion of character creation that says anything to the effect of, "While you are a character in this game, your [STR] score is X." The belts of giant strength do say this, however. And that's why a penalty does nothing while wearing it.
I get that, but as a counter example, for Armor, Chain Mail states that your AC is 16. No combination of scores, no adding anything. Your AC is 16. But you wouldn't suggest that when using the spell Slow, which states "it takes a −2 penalty to AC", that you couldn't decrease the AC because "The item says specifically your AC is 16, and therefore cannot be lower than that." This seems pretty similar to the Belt of Hill Giant Strength. "While wearing this belt, your Strength is 21. While wearing this armor, your AC is 16."
The difference is that there is no language in the Class/Abilities portion of character creation that says anything to the effect of, "While you are a character in this game, your [STR] score is X." The belts of giant strength do say this, however. And that's why a penalty does nothing while wearing it.
I get that, but as a counter example, for Armor, Chain Mail states that your AC is 16. No combination of scores, no adding anything. Your AC is 16. But you wouldn't suggest that when using the spell Slow, which states "it takes a −2 penalty to AC", that you couldn't decrease the AC because "The item says specifically your AC is 16, and therefore cannot be lower than that." This seems pretty similar to the Belt of Hill Giant Strength. "While wearing this belt, your Strength is 21. While wearing this armor, your AC is 16."
Not quite. The AC rules are fairly clear that the AC listed in the tables is a "base AC" not "set AC equal to":
Armor Class (AC). The table’s Armor Class column tells you what your base AC is when you wear a type of armor.
This is very much like your stats, which have a "Base Value" (as seen on the DDB character creation page). And even without that, you assign scores, but there is no language at all suggesting those scores cannot increase or decrease. This is wholly unlike the language of the belts.
The difference is that there is no language in the Class/Abilities portion of character creation that says anything to the effect of, "While you are a character in this game, your [STR] score is X." The belts of giant strength do say this, however. And that's why a penalty does nothing while wearing it.
I get that, but as a counter example, for Armor, Chain Mail states that your AC is 16. No combination of scores, no adding anything. Your AC is 16. But you wouldn't suggest that when using the spell Slow, which states "it takes a −2 penalty to AC", that you couldn't decrease the AC because "The item says specifically your AC is 16, and therefore cannot be lower than that." This seems pretty similar to the Belt of Hill Giant Strength. "While wearing this belt, your Strength is 21. While wearing this armor, your AC is 16."
Not quite. The AC rules are fairly clear that the AC listed in the tables is a "base AC" not "set AC equal to":
Armor Class (AC). The table’s Armor Class column tells you what your base AC is when you wear a type of armor.
This is very much like your stats, which have a "Base Value" (as seen on the DDB character creation page). And even without that, you assign scores, but there is no language at all suggesting those scores cannot increase or decrease. This is wholly unlike the language of the belts.
So if the Strength Score cannot be changed, how do we rule the Hammer of Thunderbolts? You have to have a Belt of Giant Strength and the gauntlets of ogre power. Then it states that "While you are attuned to this weapon and holding it, your Strength score increases by 4 and can exceed 20, but not 30." Is that your "natural" strength, or your strength score with the belt? Would it be 25 with the Belt of Hill Giant Strength (BoHGS), or would it be stuck at 21 unless somehow your "natural" strength was at least 18, in which case it could go up to 22 with the +4?
I'm not trying to be argumentative or pedantic or anything like that. It just seems odd to me that there would be a this relationship with Magic Items and abilities or other items that affect ability scores that isn't spelled out anywhere in the rules. There's nothing that I can find that would say "a bonus to your [Ability Score] only applies to your base [Ability Score] and not to the score granted by a Magic Item." If Someone had a Strength Score of 21 from the BoHGS and they drank a homebrew potion that added +5 to Strength, I would feel that it would kind of obviously affect their current Strength Score (21) to make it 26, and not their "natural" base score, because nothing in the rules ever suggests that (that I can find).
It seems mostly to be a "yeah, it's just understood that it works like that", rather than actually being stated in the rules.
So if the Strength Score cannot be changed, how do we rule the Hammer of Thunderbolts? You have to have a Belt of Giant Strength and the gauntlets of ogre power. Then it states that "While you are attuned to this weapon and holding it, your Strength score increases by 4 and can exceed 20, but not 30." Is that your "natural" strength, or your strength score with the belt? Would it be 25 with the Belt of Hill Giant Strength (BoHGS), or would it be stuck at 21 unless somehow your "natural" strength was at least 18, in which case it could go up to 22 with the +4?
This one is specific beats general. Since the hammer requires the belt and gauntlets, the ability must override them in order to work, so it does.
I'm not trying to be argumentative or pedantic or anything like that. It just seems odd to me that there would be a this relationship with Magic Items and abilities or other items that affect ability scores that isn't spelled out anywhere in the rules. There's nothing that I can find that would say "a bonus to your [Ability Score] only applies to your base [Ability Score] and not to the score granted by a Magic Item." If Someone had a Strength Score of 21 from the BoHGS and they drank a homebrew potion that added +5 to Strength, I would feel that it would kind of obviously affect their current Strength Score (21) to make it 26, and not their "natural" base score, because nothing in the rules ever suggests that (that I can find).
It seems mostly to be a "yeah, it's just understood that it works like that", rather than actually being stated in the rules.
The rules essentially never give any guidance on how to deal with the interactions of multiple abilities (this is not ideal, but it's what we've got), so people have to work it out themselves.
In the case of the fixed-stat-boost items, the general consensus is that, because they override your score regardless of what it is, then that override reapplies whenever your stat changes. It's not the only way to play it, but other ways lead to questions like "if I get a strength boost after wearing the gauntlets, it applies, so does it also apply if I have it before I wear the gauntlets?" and "what counts as a strength increase anyway, and why do these apply after the gauntlets, but not these?"
And if bonuses get overridden, then surely penalties should also get overridden. But then you have the weird situation where somebody with gauntlets of ogre power are fundamentally immune to being killed by a shadow, which badly weakens the monster, and also you have the situation where if they take the gauntlets off, they drop dead, which also feels off.
Nowhere I can find in the rules does it talk about "your natural Strength score" or give any indication that you have two different Strength Scores (or any ability score) at the same time.
It's because of this that I would tend to lean toward ruling it the other way entirely. That the monster attack effect essentially does nothing.
Example: You have 10 strength. You put on the belt and have 21 strength "while wearing it". You are attacked and lose 1d4 strength, but you have 21 strength while wearing the belt so you still have 21 strength. You take off the belt and now you have 10 strength.
The difference is that there is no language in the Class/Abilities portion of character creation that says anything to the effect of, "While you are a character in this game, your [STR] score is X." The belts of giant strength do say this, however. And that's why a penalty does nothing while wearing it.
I get that, but as a counter example, for Armor, Chain Mail states that your AC is 16. No combination of scores, no adding anything. Your AC is 16. But you wouldn't suggest that when using the spell Slow, which states "it takes a −2 penalty to AC", that you couldn't decrease the AC because "The item says specifically your AC is 16, and therefore cannot be lower than that." This seems pretty similar to the Belt of Hill Giant Strength. "While wearing this belt, your Strength is 21. While wearing this armor, your AC is 16."
Not quite. The AC rules are fairly clear that the AC listed in the tables is a "base AC" not "set AC equal to":
Armor Class (AC). The table’s Armor Class column tells you what your base AC is when you wear a type of armor.
This is very much like your stats, which have a "Base Value" (as seen on the DDB character creation page). And even without that, you assign scores, but there is no language at all suggesting those scores cannot increase or decrease. This is wholly unlike the language of the belts.
So if the Strength Score cannot be changed, how do we rule the Hammer of Thunderbolts? You have to have a Belt of Giant Strength and the gauntlets of ogre power. Then it states that "While you are attuned to this weapon and holding it, your Strength score increases by 4 and can exceed 20, but not 30." Is that your "natural" strength, or your strength score with the belt? Would it be 25 with the Belt of Hill Giant Strength (BoHGS), or would it be stuck at 21 unless somehow your "natural" strength was at least 18, in which case it could go up to 22 with the +4?
I'm not trying to be argumentative or pedantic or anything like that. It just seems odd to me that there would be a this relationship with Magic Items and abilities or other items that affect ability scores that isn't spelled out anywhere in the rules. There's nothing that I can find that would say "a bonus to your [Ability Score] only applies to your base [Ability Score] and not to the score granted by a Magic Item." If Someone had a Strength Score of 21 from the BoHGS and they drank a homebrew potion that added +5 to Strength, I would feel that it would kind of obviously affect their current Strength Score (21) to make it 26, and not their "natural" base score, because nothing in the rules ever suggests that (that I can find).
It seems mostly to be a "yeah, it's just understood that it works like that", rather than actually being stated in the rules.
For what it's worth, I rule this the same as you. While wearing a belt of giant strength or anything else that adjusts your strength score....that is your score. It doesn't matter where it comes from, that is your strength score. The shadows ability affects your strength score...its not affecting where you score comes from. So if you have a Str of 19 because a magical item sets your strength score to that, and you get hit by this shadow's ability...your strength score will be reduced by the 1d4 as the shadow's ability states. You don't track multiple strength scores...you have one. That's the only thing that makes sense to me. The magical item doesn't mention that it also grants immunity to Strength ability drain.
Admittedly, I can see where the counter argument has merit...but this is all made up magic so rule it how you want. I feel like the excuse that the strength from the belt comes from a magical source that states a specific number means that it can't be reduced could be abused in many different ways with other items and spells. It would also make the item even more OP since you gain immunity to ability score drain.
The difference is that there is no language in the Class/Abilities portion of character creation that says anything to the effect of, "While you are a character in this game, your [STR] score is X." The belts of giant strength do say this, however. And that's why a penalty does nothing while wearing it.
I get that, but as a counter example, for Armor, Chain Mail states that your AC is 16. No combination of scores, no adding anything. Your AC is 16. But you wouldn't suggest that when using the spell Slow, which states "it takes a −2 penalty to AC", that you couldn't decrease the AC because "The item says specifically your AC is 16, and therefore cannot be lower than that." This seems pretty similar to the Belt of Hill Giant Strength. "While wearing this belt, your Strength is 21. While wearing this armor, your AC is 16."
Not quite. The AC rules are fairly clear that the AC listed in the tables is a "base AC" not "set AC equal to":
Armor Class (AC). The table’s Armor Class column tells you what your base AC is when you wear a type of armor.
This is very much like your stats, which have a "Base Value" (as seen on the DDB character creation page). And even without that, you assign scores, but there is no language at all suggesting those scores cannot increase or decrease. This is wholly unlike the language of the belts.
So if the Strength Score cannot be changed, how do we rule the Hammer of Thunderbolts? You have to have a Belt of Giant Strength and the gauntlets of ogre power. Then it states that "While you are attuned to this weapon and holding it, your Strength score increases by 4 and can exceed 20, but not 30." Is that your "natural" strength, or your strength score with the belt? Would it be 25 with the Belt of Hill Giant Strength (BoHGS), or would it be stuck at 21 unless somehow your "natural" strength was at least 18, in which case it could go up to 22 with the +4?
I'm not trying to be argumentative or pedantic or anything like that. It just seems odd to me that there would be a this relationship with Magic Items and abilities or other items that affect ability scores that isn't spelled out anywhere in the rules. There's nothing that I can find that would say "a bonus to your [Ability Score] only applies to your base [Ability Score] and not to the score granted by a Magic Item." If Someone had a Strength Score of 21 from the BoHGS and they drank a homebrew potion that added +5 to Strength, I would feel that it would kind of obviously affect their current Strength Score (21) to make it 26, and not their "natural" base score, because nothing in the rules ever suggests that (that I can find).
It seems mostly to be a "yeah, it's just understood that it works like that", rather than actually being stated in the rules.
To be honest, I don't actually think the Hammer works as intended, as written. It's (pretty) clear that they want the bonus to apply in addition to whatever the score is set as, but we actually don't have a set of rules (or any language at all, really) that tells us how to deal with specific ("your STR score is 21 while wearing this belt") vs. specific ("your STR score is reduced by 1d4"). We, as adjudicators of the rules, have to deem one "more specific" than the other and override the other, and the language of the belt is simply stronger than the language of the Shadow's ability.
Based on language alone, the Hammer of Thunderbolts doesn't actually override the STR "setting" of the belt (unless it somehow brings your base stat up above whatever the belt would make it). But as I said above, it's pretty clear that they intended for the Hammer to be used in conjunction with any of the belts and so, as an adjudicator of the rules and the specific vs specific in this case, I'd say that the Hammer does add 4 to your already "set" STR score, even if I think that RAW, it shouldn't.
EDIT: in fact, the Hammer was updated in the new DMG (which I should have checked before posting) to actually modify the Belt because it didn't work as written before: Hammer of Thunderbolts
Hi there, Midgardians!
I was looking at the Shadow monster and it says that everytime it hits a player, it reduces their strength score in 1d4. Does that score reduction change the player's strength modifier?
Thanks in advance.
Ability score modifiers are based on the current value of the ability score, so if the ability score changes, the modifier may change.
In some cases it might not, just because multiple ability score values can have the same modifier — for instance, if your Strength is 17 and you roll a 1 on that d4, your Strength will go down to 16, but the modifier will remain +3, because that's the modifier for both 16 and 17.
Worth pointing out, since it's a thing people often ask about this, that in the 5.5e rules finishing a Long Rest resets any active ability score reductions.
pronouns: he/she/they
If I have a magic item that gives me a 19 strength, what strength do I lose?
Using the -1 example.
If I have a 10 ability and the magic item. Does my ability drop to 9, but my strength stays at 19 due to magic?
If you have a magic item that sets your ability score to a specific number while you're using it, reductions (or increases) to your natural ability score don't have any effect on that. So in your example, your Strength would still be 19 while you're using the item, but if you took off or deactivated the item, your Strength would be 9.
pronouns: he/she/they
That depends on how that item is giving you the 19. I assume that it's because it "sets" the score to 19, and so you wouldn't lose str. However, you'd still need to track it just in case you lost the item before taking your long rest and resetting the reduction.
Also because you die if your score reaches zero.
The magic item would keep your strength at 19, I think.
Could you say where that ruling comes from?
From what I could tell, if you're using a magic item like the Belt of Giant Strength, it simply replaces your Strength Score while you are wearing it. "While wearing this belt, your Strength score changes to a score granted by the belt."
The Shadow's ability says "Draining Swipe. Melee Attack Roll: +4, reach 5 ft. Hit: 5 (1d6 + 2) Necrotic damage, and the target’s Strength score [emphasis mine] decreases by 1d4." If the target's strength score was 21 (we'll say it's the Belt of Hill Giant Strength to be specific), then their natural score is completely replaced by the belt's, so it would be 21. That 21 should then be reduced by 1d4, right? Nothing about the belt says "this score cannot be reduced", it is just the new Strength Score. I can see tracking the negative to Strength in case they took off the belt (they have -6 to Strength Score because of the Shadow's attacks, and if their "natural" score is 10, when they take the belt off their score becomes 4), but I don't know why the score granted by the belt would be unable to be affected by other things.
Right. That's what it says. While wearing the belt, your Strength score is 21 (or whatever). So while you have the belt on your Strength score is 21, regardless of anything else.
Consider also that even if it didn't work that way, all you'd have to do is take the belt off and put it on again to get your 21 Strength back.
pronouns: he/she/they
Is it replaced or is it boosted by the belt? Logically it made sense when I asked, that it boosted ones strength which is why you have a flat rate/number and it was not relevant what your actual ability score is.
I get that line of thinking, I just can't help but feel like it leans on assumptions that aren't stated anywhere. I did a bit more research and it seems Jeremy Crawford did state that your "natural" score is affected by things like the Shadow's attack, but not those granted by a magic item. So my viewpoint is obviously not shared by the designers. But it DOES feel like something that is more of a "we intended it to be this way, even though we didn't write the rules like that." My best example of that is the Twinned Spell rules in 5e, where they added language later (not an errata, as far as I know, but a "suggestion on how to rule if a spell can be Twinned or not") so that a spell like Dragon's Breath couldn't be Twinned, while as written is was a perfectly acceptable candidate for Twinned Spell.
My reasoning for this is that there isn't a real difference between the Strength Score granted by your class/species/feats and the one granted by the Magic Item. The magic item says it doesn't have an effect if your strength would be equal to or greater than what the magic items sets it to. So the magic item isn't magically forcing a certain number on the character. If that were the case, even if their strength naturally was a 26, the Belt would change it to a 21 because it is magically setting a score. Instead it seems like it is enhancing the strength of the character.
You Strength Score is a set number. It is set by a combination of feats, abilities, species, class, etc. The Belt (in this example) simply gives a new place from which to get that number. I concede that Jeremy Crawford says that number cannot be changed by anything, but that just seems off to me. Nowhere I can find in the rules does it talk about "your natural Strength score" or give any indication that you have two different Strength Scores (or any ability score) at the same time. It all just seems like "this is how we wanted it to work, but we didn't bother writing that into the rules."
So I'm wrong per the developer, but I don't think my reasoning is wrong.
Thank you very much for your help ❤️
The difference is that there is no language in the Class/Abilities portion of character creation that says anything to the effect of, "While you are a character in this game, your [STR] score is X." The belts of giant strength do say this, however. And that's why a penalty does nothing while wearing it.
I get that, but as a counter example, for Armor, Chain Mail states that your AC is 16. No combination of scores, no adding anything. Your AC is 16. But you wouldn't suggest that when using the spell Slow, which states "it takes a −2 penalty to AC", that you couldn't decrease the AC because "The item says specifically your AC is 16, and therefore cannot be lower than that." This seems pretty similar to the Belt of Hill Giant Strength. "While wearing this belt, your Strength is 21. While wearing this armor, your AC is 16."
Not quite. The AC rules are fairly clear that the AC listed in the tables is a "base AC" not "set AC equal to":
This is very much like your stats, which have a "Base Value" (as seen on the DDB character creation page). And even without that, you assign scores, but there is no language at all suggesting those scores cannot increase or decrease. This is wholly unlike the language of the belts.
So if the Strength Score cannot be changed, how do we rule the Hammer of Thunderbolts? You have to have a Belt of Giant Strength and the gauntlets of ogre power. Then it states that "While you are attuned to this weapon and holding it, your Strength score increases by 4 and can exceed 20, but not 30." Is that your "natural" strength, or your strength score with the belt? Would it be 25 with the Belt of Hill Giant Strength (BoHGS), or would it be stuck at 21 unless somehow your "natural" strength was at least 18, in which case it could go up to 22 with the +4?
I'm not trying to be argumentative or pedantic or anything like that. It just seems odd to me that there would be a this relationship with Magic Items and abilities or other items that affect ability scores that isn't spelled out anywhere in the rules. There's nothing that I can find that would say "a bonus to your [Ability Score] only applies to your base [Ability Score] and not to the score granted by a Magic Item." If Someone had a Strength Score of 21 from the BoHGS and they drank a homebrew potion that added +5 to Strength, I would feel that it would kind of obviously affect their current Strength Score (21) to make it 26, and not their "natural" base score, because nothing in the rules ever suggests that (that I can find).
It seems mostly to be a "yeah, it's just understood that it works like that", rather than actually being stated in the rules.
This one is specific beats general. Since the hammer requires the belt and gauntlets, the ability must override them in order to work, so it does.
The rules essentially never give any guidance on how to deal with the interactions of multiple abilities (this is not ideal, but it's what we've got), so people have to work it out themselves.
In the case of the fixed-stat-boost items, the general consensus is that, because they override your score regardless of what it is, then that override reapplies whenever your stat changes. It's not the only way to play it, but other ways lead to questions like "if I get a strength boost after wearing the gauntlets, it applies, so does it also apply if I have it before I wear the gauntlets?" and "what counts as a strength increase anyway, and why do these apply after the gauntlets, but not these?"
And if bonuses get overridden, then surely penalties should also get overridden. But then you have the weird situation where somebody with gauntlets of ogre power are fundamentally immune to being killed by a shadow, which badly weakens the monster, and also you have the situation where if they take the gauntlets off, they drop dead, which also feels off.
It's because of this that I would tend to lean toward ruling it the other way entirely. That the monster attack effect essentially does nothing.
Example: You have 10 strength. You put on the belt and have 21 strength "while wearing it". You are attacked and lose 1d4 strength, but you have 21 strength while wearing the belt so you still have 21 strength. You take off the belt and now you have 10 strength.
For what it's worth, I rule this the same as you. While wearing a belt of giant strength or anything else that adjusts your strength score....that is your score. It doesn't matter where it comes from, that is your strength score. The shadows ability affects your strength score...its not affecting where you score comes from. So if you have a Str of 19 because a magical item sets your strength score to that, and you get hit by this shadow's ability...your strength score will be reduced by the 1d4 as the shadow's ability states. You don't track multiple strength scores...you have one. That's the only thing that makes sense to me. The magical item doesn't mention that it also grants immunity to Strength ability drain.
Admittedly, I can see where the counter argument has merit...but this is all made up magic so rule it how you want. I feel like the excuse that the strength from the belt comes from a magical source that states a specific number means that it can't be reduced could be abused in many different ways with other items and spells. It would also make the item even more OP since you gain immunity to ability score drain.
To be honest, I don't actually think the Hammer works as intended, as written. It's (pretty) clear that they want the bonus to apply in addition to whatever the score is set as, but we actually don't have a set of rules (or any language at all, really) that tells us how to deal with specific ("your STR score is 21 while wearing this belt") vs. specific ("your STR score is reduced by 1d4"). We, as adjudicators of the rules, have to deem one "more specific" than the other and override the other, and the language of the belt is simply stronger than the language of the Shadow's ability.
Based on language alone, the Hammer of Thunderbolts doesn't actually override the STR "setting" of the belt (unless it somehow brings your base stat up above whatever the belt would make it). But as I said above, it's pretty clear that they intended for the Hammer to be used in conjunction with any of the belts and so, as an adjudicator of the rules and the specific vs specific in this case, I'd say that the Hammer does add 4 to your already "set" STR score, even if I think that RAW, it shouldn't.
EDIT: in fact, the Hammer was updated in the new DMG (which I should have checked before posting) to actually modify the Belt because it didn't work as written before: Hammer of Thunderbolts