So, on facebook a DM asked for help to balance an encounter that he wants to be deadly.
The heroes consist of 5 level 3 PCs, and a level 4 DMPC tat will help them completely for this battle but will be an enemy in the future. The 3 PCs are an Artificer, a Mystic, a Druid, a Warlock, and a Paladin. The DMPC is a Wizard/ hag of some type in disguise.
The villain is an Undead Silver Dragonborn Paladin level 8. The room is 40x50 and 40' high. The DM wanted to give the villain as many of a normal paladin powers as possible and also want him to have the unrelenting force shout (or spell) either way homebrewed.
AC of 19, HP of 96 and 3 legendary resistances.
The Villain will have 3 Legendary actions per round: just one attack for 1 legendary action, 2 actions foe a shield bash, athletics fight to knock down or 3 actions for the shout (If it's the shout it knocks everyone prone, if it's the spell it uses a 2nd level slot and deals 2d8 as well as knocking everyone prone).
The villain has two feats, Shield Master and Heavy Armor Master
The villain has a magical +1 light hammer of life stealing 10%
Level 8 means that he has Lay on Hands of 40, but it can't be used on an undead.
The Light Hammer should only do 14d+4 damage (+3 for strength +1 for the weapon) On the other hand it does have range and is returning. He gets a +7 to attack so will hit 50-60% of the time
In addition, 7 spell slots 4 1st lvl 3 2nd level. Up to a possible 17d8 extra damage averaging 76.5 damage. 2nd level slots will be 20 damage so he’ll usually heal 2, 1st level will be 15.5 so he’ll usually only heal 1 possible to heal 2. Most likely will heal a total of 7 points from his attacks if he gets off all spell slots, which should be utilized in his first 7 hits.
With the legendary actions he'll have 5 attacks per round. 1st round near 60 damage most likely, 2nd round near 46.5 most likely 3rd round and all following 19.5 most likely. That's assuming an average of 16 AC for the PCs.
I compared this to the Hobgoblin Captains which are CR 3 : a hobgoblin captain is CR 3, it has only 39 health and a 17 AC, so fairly easy to take out quickly. It deals 19 damage once per turn or 28 if it actually hits twice. Has about a 50% chance to hit the average lvl 3 player. 2 of them would be given 4 attacks per round they'd have 78 health between them and hit once per turn on average each. dealing 38 damage. 3 of them would have 6 attacks per round and hit on about 1 each per round. dealing 57 damage on average. and have 117 health between them. As they are killed they will get weaker. and both their attacks per round and average damage will significantly decrease.
As you can see the AC is 10% lower, but the health is slightly higher. All of the hobgoblin damage dice were rounded down while the Paladin's I actually averaged. It's a fairly similar fight.
The life steal should steal an average of 10 health for the Villain, but won't be able to steal any after the smites are gone. 1d4+4 cannot get to 10 and you always round down on things like that. The big boost to the baddie is his damage resistance which will help him survive to the 4th round of combat.
I suggested throwing in 2 kobold minions boosting them to 20 hp and a +5 to hit to make them around CR 1/2. they'll add 5 damage per round. Here's the key though, the Villain can use his Lay on Hands ability to heal them after they are downed. It will use his whole action taking away 2 of his attacks for the round. He only has 40 Lay on Hands points so will only be able to revive them twice, either bringing the same 1 up twice or bringing each one up once. Either way it should be his priority to do this to keep the encounter balanced. If the heroes kill them they'll take the Villain's main action lowering his chance of dealing damage that round but since the minions average 5 damage per round they'll still prove an interesting distraction and make the combat feel more threatening. Also impeding powers can be used on them which will make the encounter more enjoyable for controlling characters. It won't actually make much difference. but will be a fun addition.
3 hobgoblin captains versus 5 lvl 3 and 1 lvl 4 pcs, would count as a deadly encounter ranging between deadly and hard. The action economy leans heavily towards deadly though.
In the end I saw the entire thing as balanced enough but added in a method to increase the fun. The kobolds will draw the combat into the 5th round probably, so it will be long. It will be deadly and dangerous.
This is the math to balance an encounter. If you have any requests for encounter balancing send me an email at Ricky_M_A@ymail.com or comment on here. Tell me as much as you can, I will ask further questions for clarification.
Have fun gaming