I was wondering if there is an official monster in 5th edition that has resistance against any combination of bludgeoning, piercing or slashing damage and an immunity against any combination of bludgeoning, piercing or slashing damage dealt with non-magical weapons on top of that.
While I was looking through various monster stat-blocks I noticed that resistance to bludgeoning, piercing and slashing damage is extremely rare (e.g. Treant) and it bothered me that a Rakshasa for example has almost no physical durability because when the players get to fight one, it’s likely they already have magical weapons.
I’m thinking about homebrewing a monster that has resistance to the common damage types and an immunity to the common damage types if the attacks are made with nonmagical weapons, but I wanted to know if that already exists in 5th edition because I like to stick with official material instead of inventing something totally new.
Best Answer
The only such monster is the demilich
The demilich has a number of damage immunities including from nonmagic bludgeoning, piercing, and slashing. It also has resistance against magic piercing, slashing, and bludgeoning.
There are only few monsters in the monster manual that have immunity or resistance to a single one of the three damage types and none of them have the resistance / immunity combination you ask for.
While resistance against non-magic attacks of all three damage types is pretty common, there's only a handful of monsters with immunity to them and the demilich is the only monster in the book that has any specific resistance to magic attacks of the common damage types (swarms have complete resistance against these types, i.e. against magic and nonmagic attacks).