I will be homebrewing a sentient sword that can also cast vicious mockery.   As well as standard melee weapon damage, this sword does an extra 1d4 psychic damage and causes the target to have disadvantage on their next turn.

So not only does this sword deal more damage to the target, it makes the wielder less likely to take damage, by forcing the target to have disadvantage.

It does this with every successful hit.  

So basically puts the enemy at a constant disadvantage.

There is a drawback to using this sword in that it twists the mind if the one who wields it, making them much more susceptible to being mind-controlled by fiends.

I am not sure what level this kind of weapon would be suited for though, any thoughts?

Given that that’s basically a very specific version of the Eldritch Knight’s 7th-level feature but for free (no additional action cost), I’d put it in the 7-10 range.

The effect is similar to frostbite as well which is also a cantrip. The difference with your weapon being no save but there is an attack roll.

I'd put it in the lvl 2-4 range.

Quote from SocialFoxes >>

I will be homebrewing a sentient sword that can also cast vicious mockery.   As well as standard melee weapon damage, this sword does an extra 1d4 psychic damage and causes the target to have disadvantage on their next turn.

So not only does this sword deal more damage to the target, it makes the wielder less likely to take damage, by forcing the target to have disadvantage.

It does this with every successful hit.  

So basically puts the enemy at a constant disadvantage.

There is a drawback to using this sword in that it twists the mind if the one who wields it, making them much more susceptible to being mind-controlled by fiends.

I am not sure what level this kind of weapon would be suited for though, any thoughts?

Could you clarify something, are you saying this sword can cast vicious mockery and do all the other stuff that is basically vicious mockery? Or are you just reiterating what vicious mockery does? Also, what would be the DC? Would it be based off the user or would it be fixed for the sword?

Also what does "making them much more susceptible to being mind-controlled by fiends" mean? Because that doesn't really mean anything in game terms; is it disadvantage on wisdom saving throws against fiends? Automatically failing saving throws against being charmed? Even if the latter, that's not much of a downside, seeing as how few fiends actually have charm effects.

If we're taking a sentient sword that lets you cast vicious mockery and gives you some kind of penalty on being 'mind controlled', I'd expect it to be a rare tier weapon at least, which is 5th level or higher according to the DMG.

Quote from Davedamon >>

Quote from SocialFoxes >>

I will be homebrewing a sentient sword that can also cast vicious mockery.   As well as standard melee weapon damage, this sword does an extra 1d4 psychic damage and causes the target to have disadvantage on their next turn.

So not only does this sword deal more damage to the target, it makes the wielder less likely to take damage, by forcing the target to have disadvantage.

It does this with every successful hit.  

So basically puts the enemy at a constant disadvantage.

There is a drawback to using this sword in that it twists the mind if the one who wields it, making them much more susceptible to being mind-controlled by fiends.

I am not sure what level this kind of weapon would be suited for though, any thoughts?

Could you clarify something, are you saying this sword can cast vicious mockery and do all the other stuff that is basically vicious mockery? Or are you just reiterating what vicious mockery does? Also, what would be the DC? Would it be based off the user or would it be fixed for the sword?

Also what does "making them much more susceptible to being mind-controlled by fiends" mean? Because that doesn't really mean anything in game terms; is it disadvantage on wisdom saving throws against fiends? Automatically failing saving throws against being charmed? Even if the latter, that's not much of a downside, seeing as how few fiends actually have charm effects.

If we're taking a sentient sword that lets you cast vicious mockery and gives you some kind of penalty on being 'mind controlled', I'd expect it to be a rare tier weapon at least, which is 5th level or higher according to the DMG.

 From the looks of it the "D.C" would be the targets A.C more or less. They say "every successful hit" yet unless this sword casts Vicious mockery every time you hit the target, it would need a D.C. My suggestion is because this weapon is sentient with what is pretty much a curse make it lvl 7 and up. With a D.C between 16-18 and a clearer idea on how Vicious mockery would work.

Quote from Davedamon >>

Quote from SocialFoxes >>

I will be homebrewing a sentient sword that can also cast vicious mockery.   As well as standard melee weapon damage, this sword does an extra 1d4 psychic damage and causes the target to have disadvantage on their next turn.

So not only does this sword deal more damage to the target, it makes the wielder less likely to take damage, by forcing the target to have disadvantage.

It does this with every successful hit.  

So basically puts the enemy at a constant disadvantage.

There is a drawback to using this sword in that it twists the mind if the one who wields it, making them much more susceptible to being mind-controlled by fiends.

I am not sure what level this kind of weapon would be suited for though, any thoughts?

Could you clarify something, are you saying this sword can cast vicious mockery and do all the other stuff that is basically vicious mockery? Or are you just reiterating what vicious mockery does? Also, what would be the DC? Would it be based off the user or would it be fixed for the sword?

Also what does "making them much more susceptible to being mind-controlled by fiends" mean? Because that doesn't really mean anything in game terms; is it disadvantage on wisdom saving throws against fiends? Automatically failing saving throws against being charmed? Even if the latter, that's not much of a downside, seeing as how few fiends actually have charm effects.

If we're taking a sentient sword that lets you cast vicious mockery and gives you some kind of penalty on being 'mind controlled', I'd expect it to be a rare tier weapon at least, which is 5th level or higher according to the DMG.

Sorry, I will clarify.  

If a melee attack using this sword succeeds, then upon contact, the sword itself casts vicious mockery.  However, the target does not get to make a WIS save and automatically takes an additional 1d4 psychic and has disadvantage on their next turn. An auto succeeding vicious mockery cantrip if you will.  

When I said, the sword twists the mind of the user and makes them more susceptible to being mind-controlled by fiends, that is pretty much what it does.  Mechanically, this would mean that the user had disadvantage on WIS saves against fiends.  So the user of this sword would have disadvantage against spells like suggestion and other spells, abilities and attacks that a fiend can use, that might require a WIS save.

I am making it much more likely that the user of this sword could be persuaded, through mind-altering spells or abilities to join a friend. Or that a friend would, at the very least, find it easier to control the actions of the user of the sword.  Think of anime like Swordgai, in which demon-possessed swords give their wields an enormous advantage in a fight. Then ultimately possess their users — turning them into monsters, under the control of a demon.

Only in the case of this sword, the one behind it is a devil.

The appropriate level range for the sword would depend on precisely what it does.

Does the blade actually mock the target?  If so, does it get a save, and do targets which cannot understand language still suffer the effect?
What does "vulnerable to mind control by fiends" mean?  As Davedamon said, the actual mechanics of that effect are unclear.  Disadvantage on Wis saves?  Do fiends get advantage on Charisma against you?  Something else?  Furthermore, how common would fiends be in the game in which this sword is being considered?

You'd have to actually build the sword before people could give more than a very rough guess, and people's personal biases will also swing your results.  Some folks are fine with magic items of that level of power towards the end of Tier 1 play; some folks would never be okay with giving their player a sword that inflicted 'automatic' disadvantage on attacks against them.

Quote from Wysperra >>

The effect is similar to frostbite as well which is also a cantrip. The difference with your weapon being no save but there is an attack roll.

I'd put it in the lvl 2-4 range.

Giving a character an entire free Action (even if it's only one particular Action) every single turn is incredibly over-powered for that level range. "Every turn, you can make an attack AND cast a cantrip, at-will, forever." That's not a second-level item.

Quote from SagaTympana >>

Quote from Wysperra >>

The effect is similar to frostbite as well which is also a cantrip. The difference with your weapon being no save but there is an attack roll.

I'd put it in the lvl 2-4 range.

 

Giving a character an entire free Action (even if it's only one particular Action) every single turn is incredibly over-powered for that level range. "Every turn, you can make an attack AND cast a cantrip, at-will, forever." That's not a second-level item.

 Other weapons that deal extra damage just do extra damage, usually in the 1d6 to 1d10 range. The effect of the sword is 1d4 plus giving disadvantage on the first attack with 5ft range. 

given enough space, Viscous Mockery by itself can pummel a target forever. The sword needs a successful melee attack. 

Disadvantage on one attack isn't that big a deal by level 5+ in which multiple targets is common, and enemies with multi-attack are common. By level 5+ there are multiple ways to overcome disadvantage. The effect fades after one turn and doesn't affect skills or spells that require saves, only attacks. It's nice but not overwhelming. At level 2-4 the bonus will be meaningful but will fade over time.

To clarify, does the sword inflict disadvantage for the next turn as you've said or does it inflict disadvantage on the next attack as vicious mockery does?  If it's the whole turn, that makes for a significantly more powerful weapon.

Quote from Lunali >>

To clarify, does the sword inflict disadvantage for the next turn as you've said or does it inflict disadvantage on the next attack as vicious mockery does?  If it's the whole turn, that makes for a significantly more powerful weapon.

 I'm fair certain the OP wanted to mimic the effects of Vicious Mockery so it would be next attack.

Assuming only the next attack, damage and impact is probably no worse than a Flame Tongue so I would say it is Rare.  It does worse damage, and the damage is additive based on the hit.  Assuming your intent is disadvantage on the next attack like Vicious Mockery it isn't really overpowered, as long as the damage doesn't exceed 2d4 at most, its balanced enough.

To me it seems roughly on par with a +2 weapon. The extra 1d4 damage is a little more than 2 on average, the disadvantage on next attack is a little better than "+2 to hit" when enemies get only one attack but not as good when enemies get multiple attacks. +2 weapons seem decent to give a party at about level 10 or so, give or take a few levels, so that's about where I'd put this one.

I'd say it's too powerful up to level 6, reasonable at levels 7-14 (going from very good to meh over that level range) and unimpressive above that.

I don't know how to factor in the extra "Weakness to mind control" - seems more of a thematic thing rather than something that would come up a lot, but it depends on how you plan to DM it. If you're gonna lean heavy into the mind-controlling fiends then this weapon obviously becomes weaker.

If it is just a free vicious mockery on hit and a mild curse, I'd say it is an ~uncommon weapon appropriate for a level 4 or higher character.

I don't know, an automatic Vicious Mockery on a hit is powerful because it'll cascade; each hit means you're more likely to hit again and proc another pseudo-vicious mockery.

And the 'downside' is borderline trivial; disadvantage on wis saves against fiends, that's not a consistent weakness unless you're playing DiA or OotA. 

This would be a rare item at least, if not very rare. 

Quote from Davedamon >>

I don't know, an automatic Vicious Mockery on a hit is powerful because it'll cascade; each hit means you're more likely to hit again and proc another pseudo-vicious mockery. 

 How are you more likely to hit? Vicious mockery doesn't grant advantage.

The way I see it, +1 weapons are uncommon, +2 weapons are rare. This falls right between them (+2.5 average damage, no hit bonus). I suppose it could be closer to rare because of imposed disadvantage, but then it has a curse (albeit a pretty weak one) which usually lowers rarety.

As long as the curse also includes the usual "refuse to part with and disadvantage with other weapons" clause that cursed weapons usually have, uncommon sounds right.

To give you some lore surrounding this sword and the other things I eventually intend to brew:

It may seem like the "curse" is pretty weak and not much of a downside.  In a campaign without fiends or in which fiends are very rare, this would be true.  However, this weapon is for use in a setting where fiends are relatively common and active.

Both Devils and Demons have created weapons and armour and even everyday objects that they have allowed to fall into the hands of mortals with the intent of either acquiring souls or to conscript mortals into their immortal armies.  They are especially interested in powerful mortals; like adventures or heroes, as these mortals often make great commanders once transformed.

The cursed thing might remain relatively dormant, seeming to provide a benefit to the user, without a real cost.  In reality, though, it is twisting the user's mind, warping their perspective of reality and preparing them for the time when it's true master decides to exert their control.

The fiends make no secret about this.  Each thing that they have created in engraved with a warning and gives the user the chance to discard it.  Once used for it's intended purpose; however, the user enters into a binding contract in which no lawful person, could in good faith find fault.  

In the case of Demons, being that they are more chaotic than Devils, and not ones to put much stock in the law or contracts, this same process takes the form of "might makes right."  A battle of wills, in which the winner is almost always the curse.

Of course, even Demons have engraved the things that they have created, giving potential users the chance to walk away.  In the cases of both Devils and Demons though, the warnings are engraved in the oldest and highest forms of Infernal or Abyssal, meaning that few mortals can read the warnings in the first place and of those who can, only a fraction would truly comprehend their meaning.  Both take the view that "if mortals are too stupid or lazy to learn our languages, then it's not our fault and we can't be held accountable".

I am still working on the lore for this stuff.  So I would start with just the one sword first as a sort of test, to see how it worked.

Eventually, though, I want to create a whole raft of weapons and armour and items, each flavoured to the specific fiend who created them or commissioned their creation.

I like it!

Sounds good. If the curse is something that would come into play decently often, then this is more on par with a +1 weapon rather than a +2 weapon, so probably suitable around levels 3-7.