Yeah I'll take a bite. I have a spreadsheet that helps me spit out a CR based on the guidelines from the DMG. According to it, your Slaad clocks in at a CR of ~17.25. Some monsters at that CR have resistances to nonmagical BPS damage, and immunities to energy damage that boost their effective HP. With the current battery of resistances, a CR 19 monster doesn't have much more defensive power than one without those same resistances.
Some notes: the Chaos Spittle ability lacks a range. You may want to update that to be "One target within XX feet that the Slaad can see...". Also, the multiattack ability refers to a greatsword that isn't listed.
I think giving it resistance to nonmagical bludgeoning, piercing, and slashing damage would be appropriate. Almost every CR 19+ monster has that, although some have that waived for silvered weapons. In 3e, white slaads were epic level monsters with high damage resistance to weapons with less than a +5 bonus, so I'd say that the above makes sense in 5e.
The DMG also places CR 19 monsters as having damage per round in the range of 117-122. Supposing your slaad uses its spittle every third turn, then uses the rest of its turns to use multiattack, that puts its average damage per round at somewhere south of 75. You could probably stand to make chaos spittle more potent, since it drags down the average in turns where it is used. Let's assume it hits and it sticks to a creature for three more rounds. The average of 10d4 + 5d4 + 5d4 + 5d4 is 61 damage, while a multiattack averages 2d8+8 + 2d6 + 2*(2d10+8 + 3d6) which is 17+7 + 2*(19+10) = 82 damage (do check my math lol).
If the average damage for chaos spittle were closer to 75-80, and it had the resistances, then that would bump the calculated CR to slightly north of 19.
Of course, this is situational. A party without the means to remove the chaos spittle would be doomed no matter how much damage it does. Taking Juiblex's corrupting touch by contrast, chaos spittle is much more difficult to remove, and many other abilities specify a time limit on how long the attack deals damage.
Corrupting Touch (Costs 2 Actions). Melee Weapon Attack: +14 to hit, reach 10 ft., one creature. Hit: 21 (4d6 + 7) poison damage, and the target is slimed. Until the slime is scraped off with an action, the target is poisoned, and any creature, other than an ooze, is poisoned while within 10 feet of the target.
Edit: Also, the average damage of the bite attack is incorrect. It should be 17 piercing damage on average.
Thanks for all the tips. Now what about spells? I know part of the reason the death slaad’s CR is as high as it is is due to its spellcasting. Does your excel sheet take that into account?
I manually calculate damage per round, which incorporates spells. For spells that don't deal damage I recalculate the CR by using the monster's save DC instead of its attack bonus. The DMG advises homebrewers to use one or the other based on which is more relevant to the monster's attack patterns. In this case, I'm flipping back and forth. There is definitely an art to it as much as science.
As for the spells you have, general guidance is to use the most damaging options when calculating DPR. A fireball deals an average of 28 (8d6) damage, which I assume hits two enemies, for 56 DPR. Cloudkill has an average of 22 (5d8) damage, or 44 for two characters. Unless a monster has a way to limit movement, it'd be hard to see cloudkill hitting the same creatures for more than one round. The issue with spells is that, sans legendary actions, they generally take the entire action of the monster, so they need to hit hard to be counted as the "best" option for attacking. You may want to consider legendary actions for that reason, although it depends on whether you see the slaad acting alone or with a crew. Another option is to specify that the slaad can cast those spells at a higher level. Suppose you wanted that fireball to track more closely with the average damage of multiattack (82), you could advance the fireball to say 6th-level, dealing an average of 38 (11d6) damage, which amounts to 76 damage for the average round, but I might not keep it as an "at-will" spell in that case. The key assumption is that on average two creatures are going to get hit and fail their saves.
Yeah, some art required. And a huge caveat, the DMG calculations are less reliable for high-level monsters, since battles with high-level PCs tend to have more moving parts and complications, such as the inclusion of magic items, and spells that have substantial effects without damage (maze, imprisonment, etc.).
I’ve never been good at balancing monsters, so I could use a hand.
https://www.dndbeyond.com/monsters/796858-white-slaad
Yeah I'll take a bite. I have a spreadsheet that helps me spit out a CR based on the guidelines from the DMG. According to it, your Slaad clocks in at a CR of ~17.25. Some monsters at that CR have resistances to nonmagical BPS damage, and immunities to energy damage that boost their effective HP. With the current battery of resistances, a CR 19 monster doesn't have much more defensive power than one without those same resistances.
Some notes: the Chaos Spittle ability lacks a range. You may want to update that to be "One target within XX feet that the Slaad can see...". Also, the multiattack ability refers to a greatsword that isn't listed.
Dang, both things I should have caught. Should I give him more resistances? Maybe add an extra saving throw proficiency?
I think giving it resistance to nonmagical bludgeoning, piercing, and slashing damage would be appropriate. Almost every CR 19+ monster has that, although some have that waived for silvered weapons. In 3e, white slaads were epic level monsters with high damage resistance to weapons with less than a +5 bonus, so I'd say that the above makes sense in 5e.
The DMG also places CR 19 monsters as having damage per round in the range of 117-122. Supposing your slaad uses its spittle every third turn, then uses the rest of its turns to use multiattack, that puts its average damage per round at somewhere south of 75. You could probably stand to make chaos spittle more potent, since it drags down the average in turns where it is used. Let's assume it hits and it sticks to a creature for three more rounds. The average of 10d4 + 5d4 + 5d4 + 5d4 is 61 damage, while a multiattack averages 2d8+8 + 2d6 + 2*(2d10+8 + 3d6) which is 17+7 + 2*(19+10) = 82 damage (do check my math lol).
If the average damage for chaos spittle were closer to 75-80, and it had the resistances, then that would bump the calculated CR to slightly north of 19.
Of course, this is situational. A party without the means to remove the chaos spittle would be doomed no matter how much damage it does. Taking Juiblex's corrupting touch by contrast, chaos spittle is much more difficult to remove, and many other abilities specify a time limit on how long the attack deals damage.
Corrupting Touch (Costs 2 Actions). Melee Weapon Attack: +14 to hit, reach 10 ft., one creature. Hit: 21 (4d6 + 7) poison damage, and the target is slimed. Until the slime is scraped off with an action, the target is poisoned, and any creature, other than an ooze, is poisoned while within 10 feet of the target.
Edit: Also, the average damage of the bite attack is incorrect. It should be 17 piercing damage on average.
Thanks for all the tips. Now what about spells? I know part of the reason the death slaad’s CR is as high as it is is due to its spellcasting. Does your excel sheet take that into account?
I manually calculate damage per round, which incorporates spells. For spells that don't deal damage I recalculate the CR by using the monster's save DC instead of its attack bonus. The DMG advises homebrewers to use one or the other based on which is more relevant to the monster's attack patterns. In this case, I'm flipping back and forth. There is definitely an art to it as much as science.
As for the spells you have, general guidance is to use the most damaging options when calculating DPR. A fireball deals an average of 28 (8d6) damage, which I assume hits two enemies, for 56 DPR. Cloudkill has an average of 22 (5d8) damage, or 44 for two characters. Unless a monster has a way to limit movement, it'd be hard to see cloudkill hitting the same creatures for more than one round. The issue with spells is that, sans legendary actions, they generally take the entire action of the monster, so they need to hit hard to be counted as the "best" option for attacking. You may want to consider legendary actions for that reason, although it depends on whether you see the slaad acting alone or with a crew. Another option is to specify that the slaad can cast those spells at a higher level. Suppose you wanted that fireball to track more closely with the average damage of multiattack (82), you could advance the fireball to say 6th-level, dealing an average of 38 (11d6) damage, which amounts to 76 damage for the average round, but I might not keep it as an "at-will" spell in that case. The key assumption is that on average two creatures are going to get hit and fail their saves.
Yeah, some art required. And a huge caveat, the DMG calculations are less reliable for high-level monsters, since battles with high-level PCs tend to have more moving parts and complications, such as the inclusion of magic items, and spells that have substantial effects without damage (maze, imprisonment, etc.).