Necromancers have the toughest homonculi

[TheUser]

It is slightly off-topic but can you please explain what is so synergetic with Inured to Undeath and Magic Jar?

Key to all of this is that throughout the whole process "You retain the benefit of your own class features. If the target has any class levels, you can’t use any of its class features."

Magic Jar has a few design nuances to differentiate it from Wildshape or Shapechange such that when you possess a new body all your class levels still contribute to your maximum HP (it lacks the "You assume the hit points and Hit Dice of the new form" clause). If you try to extrapolate what class levels represent contributing to HP means narratively it follows; you gain experience in avoiding death during combat, this applies while you're still using a humanoid body type (Magic Jar) and doesn't when you turn into a Bear or a Ogremoch (Wildshape/Shapechange).

So if you possess a creature like say...a CR 13 Warlord your maximum HP is surges up to 319.

The other key element is that you have never lost access to Inured to Undeath. So if the possession ends the Necromancer has 319 HP forever because their "maximum hit points cannot be reduced." and all the replacements are replacements to "your" stat block.

So yeah... RAW, Inured to Undeath is bonkers.




To digress back to the conversation, anyone thinking that spending hit dice as a necromancer is troublesome, I refer you to Grim Harvest, the feature which heals 2 HP per kill per spell level. So long as the spell deals damage on the enemy's turn (Wall of Fire, Evard's Black Tentacles, Sickening Radiance, Flaming Sphere etc. etc.) the healing gets pretty nuts. You'll probably hardly ever need to spend hit dice if you use damage spells that play around this feature.

My go-to example that I wheel out is wall of fire killing 3 enemies, that heals 24 HP which is equivalent to a free level 4 cure wounds.