Bloodthirster

Diabolical Restoration. If the Bloodthirster dies outside the Warp, its body disappears in sulfurous smoke, and it gains a new body instantly, reviving with all its Hit Points somewhere within the Warp.

Fear Aura. The Bloodthirster emanates an aura in a 20-foot Emanation while it doesn’t have the Incapacitated condition. Wisdom Saving Throw: DC 21, any enemy that starts its turn in the aura. Failure: The target has the Frightened condition until the start of its next turn. Success: The target is immune to this pit fiend’s aura for 24 hours.

Magic Resistance. The Bloodthirster has Advantage on saving throws against spells and other magical effects.

Multiattack. The pit fiend makes one Warpflame breath attack and two Exalted Axe attacks.

Exalted Axe. Melee Attack Roll: +16, reach 10 ft. Hit: 22 (4d8 + 10) Fire damage plus 9 [rollable](3d6); 

Warpflame breath attack (Recharge 5-6) Dexterity Saving Throw: DC 24, each creature in a 30-foot Cone. Failure: 18 (6d6) Fire damage. Success: Half damage.

Houndmaster: If a Bloodhound of Khorne is within sight of the Bloodthirster and the Bloodhound can hear the Bloodthrister, the bloodthirster can command the bloodhound to do one of the following two things: Move its full movement speed or make one attack to an enemy within range. The Bloodhound of khorne must use it's reaction to do this.