Chosen

Berserk. Whenever the Chosen starts its turn with 50 hit points or fewer, roll a d6. On a 5 or 6, the Chosen goes berserk. On each of its turns while berserk, the Chosen attacks the nearest creature it can see. If no creature is near enough to move to and attack, the Chosen attacks an object, with preference for an object smaller than itself. Once the Chosen goes berserk, it continues to do so until it is destroyed or regains all its hit points.

Regeneration. The Chosen regains 10 hit points at the start of its turn. If the Chosen takes acid damage, this trait doesn’t function at the start of the Chosen’s next turn. The Chosen’s body is destroyed only if it starts its turn with 0 hit points and doesn’t regenerate.

Sign of Strength. Whenever the Chosen has to make a Strength saving throw, he can treat a roll of 9 or lower as a 10.

Sign of Resilience. Whenever the Chosen has to make a Constitution saving throw, he can treat a roll of 9 or lower as a 10.

Innate Spellcasting. The Chosen's innate spellcasting ability is Intelligence (spell save DC 15). It can innately cast the following spells, requiring no material components:

At will: alter self, detect thoughts, eldritch blast, thaumaturgy

3/day each: acid arrow, bane, command, crown of madness

Multiattack. The Chosen makes two slam attacks, or casts one of its innate spells.

Slam. Melee Weapon Attack: +8 to hit, reach 5 ft., one target. Hit: 13 (2d8 + 5) bludgeoning damage.