So i'm new to home brew and I'm very confused about how CR works, especially above CR 20. I've tried to get a vague idea by looking at other monsters on here but some of them seem to overestimate and others seem to underestimate. Could you please give me advice about how to determine the CR of the monster I made? I thought it was CR 30 but looking at some other completely OP CR 30 monsters on here that seems to be a pretty low estimate.
8 Defense CR. (This is determined by AC and HP which I should point out make no sense on your monster. It's DEX mod is +5, which would give it 15 AC unarmored, but it has "natural armor" of 14. It's large, so should use a d8 hit die and with a +4 CON mod, its HP should be (d8+4)×number of hit dice).
24 Offensive CR (roughly). Based on damage (adjusted for high likelihood of crit on unconscious or stunned target).
So average expected CR16.
Special adjustments: legendary resistance makes Def CR13. I'm also going to give it ×2 effective HP because of all the action denial effects it has, and a ×1.25 effective HP for undefined healing options, bringing its defense CR to 23. Lets also give it +2 effective attack bonus for advantage on stunned/prone targets, and just and +50 first turn damage for possible instakill effect, bringing offensive CR to roughly 25.
Final CR 24, maybe higher. I do recommend changing far realm energy to not have that chance to instantly kill PCs before initiative. It also has too many Gotcha type abilities: try to communicate "gotcha, your character is crippled for days," try to heal in battle "gotcha, you just died," try to cast a spell on it "gotcha, I can cast anything back at you." It can also potentially full heal every turn with summon aberration, power absorption, cruel mercy combo to make a full health copy of itself every turn (though the original will die each time because of bad design).
This battle will go 1 of 2 ways. Either the PCs will role high initiative and get good rolls and kill it round 1 but still some lasting madness for a while, or half the party will be put unconscious in the first round (it gets 3-4 tries with 33% success) and be TPK'd without getting a single turn.
Hi, thanks for the reply. I definitely get what you mean by all the gotcha abilities. I think I'll remove the Eldritch essence and just include the full description for Unyielding essence as it provides immunity against those things without any penalty for trying. I also changed reflect energy so that it can't use actions or legendary actions for an amount of rounds equal to the level of the spell instead of turns. Mostly I just added that ability to prevent people from instakilling it with wish or some other op 9th level spell. Finally, I nerfed negative energy aura to only damage for half of what would have been healed.
To try to fix the super high TPK potential I changed psychic storm so if you fail the saving throw you just become prone for one round, though this happens with 100% chance. I also made it so psychic glare only stuns for one round. Finally, I made far realm energy only have the capability to add one level of insanity if you failed the saving throw. To make it a little stronger after the nerfs I slightly increased the damage of all the abilities. I also made it so psychic glare would nullify saving throw proficiencies next time the target makes a saving throw.
I'm also little confused about how it can full heal every turn. I think you're saying it can take the power to clone itself from an aberration it spawns. Though it can only summon an aberration of CR 9 or lower using 3 legendary actions and I don't think any have cloning powers. Also, where does cruel mercy play into this and why does the original die? Or are you saying it can spawn itself but with super low HP to artificially lower the CR below 9. Then instakill the clone with absorb power and use cruel mercy to reanimate itself by sacrificing all of its health. Though this accomplishes nothing since it can't reanimate itself with more health than it had originally.
I also fixed the defense stats of the monster to make logical sense, it now has AC 18 because of natural armour.
I'm also little confused about how it can full heal every turn. I think you're saying it can take the power to clone itself from an aberration it spawns. Though it can only summon an aberration of CR 9 or lower using 3 legendary actions and I don't think any have cloning powers. Also, where does cruel mercy play into this and why does the original die? Or are you saying it can spawn itself but with super low HP to artificially lower the CR below 9. Then instakill the clone with absorb power and use cruel mercy to reanimate itself by sacrificing all of its health. Though this accomplishes nothing since it can't reanimate itself with more health than it had originally.
I'll explain. For 1 legendary action before its turn, it can summon a CR3 or less aberration, lets say flumph. On its turn, it then uses power absorption to kill the flumph doesn't matter what ability it gets. Now with cruel mercy, since it just killed a creature, that creature can become a copy of LoIC. As a copy, it now has the same max HP as LoIC, so original LoIC dies from taking that amount of damage, but now there is a new undamaged creature with the same stats that has not acted yet this round.
Also, there is no mechanical difference between a turn and a round, so you didn't change reflect energy at all.
So i'm new to home brew and I'm very confused about how CR works, especially above CR 20. I've tried to get a vague idea by looking at other monsters on here but some of them seem to overestimate and others seem to underestimate. Could you please give me advice about how to determine the CR of the monster I made? I thought it was CR 30 but looking at some other completely OP CR 30 monsters on here that seems to be a pretty low estimate.
The monster: https://www.dndbeyond.com/monsters/875831-dominus-supputari-chaco-lord-of-impenetrable-chaos
This isn't site feedback, but I'll use the DMG creating a monster guide for you.
8 Defense CR. (This is determined by AC and HP which I should point out make no sense on your monster. It's DEX mod is +5, which would give it 15 AC unarmored, but it has "natural armor" of 14. It's large, so should use a d8 hit die and with a +4 CON mod, its HP should be (d8+4)×number of hit dice).
24 Offensive CR (roughly). Based on damage (adjusted for high likelihood of crit on unconscious or stunned target).
So average expected CR16.
Special adjustments: legendary resistance makes Def CR13. I'm also going to give it ×2 effective HP because of all the action denial effects it has, and a ×1.25 effective HP for undefined healing options, bringing its defense CR to 23. Lets also give it +2 effective attack bonus for advantage on stunned/prone targets, and just and +50 first turn damage for possible instakill effect, bringing offensive CR to roughly 25.
Final CR 24, maybe higher. I do recommend changing far realm energy to not have that chance to instantly kill PCs before initiative. It also has too many Gotcha type abilities: try to communicate "gotcha, your character is crippled for days," try to heal in battle "gotcha, you just died," try to cast a spell on it "gotcha, I can cast anything back at you." It can also potentially full heal every turn with summon aberration, power absorption, cruel mercy combo to make a full health copy of itself every turn (though the original will die each time because of bad design).
This battle will go 1 of 2 ways. Either the PCs will role high initiative and get good rolls and kill it round 1 but still some lasting madness for a while, or half the party will be put unconscious in the first round (it gets 3-4 tries with 33% success) and be TPK'd without getting a single turn.
Hi, thanks for the reply. I definitely get what you mean by all the gotcha abilities. I think I'll remove the Eldritch essence and just include the full description for Unyielding essence as it provides immunity against those things without any penalty for trying. I also changed reflect energy so that it can't use actions or legendary actions for an amount of rounds equal to the level of the spell instead of turns. Mostly I just added that ability to prevent people from instakilling it with wish or some other op 9th level spell. Finally, I nerfed negative energy aura to only damage for half of what would have been healed.
To try to fix the super high TPK potential I changed psychic storm so if you fail the saving throw you just become prone for one round, though this happens with 100% chance. I also made it so psychic glare only stuns for one round. Finally, I made far realm energy only have the capability to add one level of insanity if you failed the saving throw. To make it a little stronger after the nerfs I slightly increased the damage of all the abilities. I also made it so psychic glare would nullify saving throw proficiencies next time the target makes a saving throw.
I'm also little confused about how it can full heal every turn. I think you're saying it can take the power to clone itself from an aberration it spawns. Though it can only summon an aberration of CR 9 or lower using 3 legendary actions and I don't think any have cloning powers. Also, where does cruel mercy play into this and why does the original die? Or are you saying it can spawn itself but with super low HP to artificially lower the CR below 9. Then instakill the clone with absorb power and use cruel mercy to reanimate itself by sacrificing all of its health. Though this accomplishes nothing since it can't reanimate itself with more health than it had originally.
I also fixed the defense stats of the monster to make logical sense, it now has AC 18 because of natural armour.
I'll explain. For 1 legendary action before its turn, it can summon a CR3 or less aberration, lets say flumph. On its turn, it then uses power absorption to kill the flumph doesn't matter what ability it gets. Now with cruel mercy, since it just killed a creature, that creature can become a copy of LoIC. As a copy, it now has the same max HP as LoIC, so original LoIC dies from taking that amount of damage, but now there is a new undamaged creature with the same stats that has not acted yet this round.
Also, there is no mechanical difference between a turn and a round, so you didn't change reflect energy at all.