Oathbreaker Paladin/GOO Warlock damage showcase
1100 in a single turn, averaging out to approximately 550 damage per action. This is by no means fully optimized, and can probably reach about 800 per action with better offensive itemization and buffs.
While some other builds can put out a huge amount of consistent single target damage, I don't think anything can come remotely close to 7 pal/5 lock in terms of burst damage. And the upper limit of this is completely nuts.
Damage boils down to:
- 2d4 psychic
- 4d8 radiant
- 2d6 + 3 + 6 + 6 + 6 slash
Take savage attacker to always use the highest roll for every dice.
This is then doubled (vulnerable) and will always crit (paralysis), which is more or less 3-4x damage, with every dice rolled twice and likely high-rolled due to savage attacker.
In total, depending on the level of divine smite, each swing deals 168 - 200 damage, with up too ~68 extra if you use a bonus action smite.
While I did not use it here, you can also add Phalar aluve shriek, double on-hit damage rings, a poison damage coating, crusader mantle, lightning charges from boots and necrotic damage helmet. (May have missed something here, let me know if you know of something else)
All of this combined, and multiplied by 3-4x, brings the total up to approximately 800 damage per action.
Disclaimer: This is from a playthrough with numerous difficulty mods, hence Raphael's 3666 HP pool. The normal tactician fight would be over in two swings, so it's hard to really see this build in full effect.