Medium Aberration, Chaotic Evil

Armor Class: 17 (Half-Plate + Shield)

Hit Points: 76 (8d8+40)

Speed: 20 ft.

STR 19/+4

DEX 10/+0

CON 20/+5

INT 6/-2

WIS 8/-1

CHA 5/-3

Saving Throws: Wis +1

Damage Resistances: Cold, Psychic

Damage Immunities: Necrotic (Special)

Condition Immunities: Blinded, Exhaustion, Charmed, Frightened

Senses: Blindsight 60 ft., Passive Perception 11

Languages: Common and Deep Speech; Understands but can’t Speak

Challenge: 3

Proficiency Bonus: +2

Eldritch Vigour. When the Bulwark would take necrotic damage, it not only ignores the damage, but also regains hit points equal to the necrotic damage it would take. 

Unnatural Reconstitution. Bloating Bulwark can only die if it is reduced to 0 Hit Points by an effect dealing radiant damage, or if it takes radiant damage while at 0 Hit Points.  At the start of its turn, if the Bulwark is at 0 Hit Points, it immediately regains half of its maximum Hit Points. 

Bloated Eruption. When the Bloating Bulwark is reduced to 0 Hit Points, its body bursts in a shower of poisonous bile and brine. All creatures within 10 feet of it must make a DC 14 Constitution saving throw, taking 13(2d12) Poison damage on a failure and becoming poisoned until the end of their next turn, or only half the damage and not being poisoned on a success.

Crushing Force. Bulwark deals extra 14(4d6) bludgeoning damage to prone creatures.

Actions. 

• Heavy Maul. Melee Weapon Attack: +6 to hit, reach 5 ft., one target. Hit: 11(2d6+4) bludgeoning damage plus extra 3 (1d6) necrotic damage. If the target is large or smaller, it must make a DC 14 Strength saving throw, being knocked prone on a failure. 
• Unrelenting March. The Bulwark gains extra 10 feet of movement, and the ability to move though the space of other creatures of creature size large or smaller. Each time it moves through a creature’s space, the creature must make a DC 14 Strength saving throw, being knocked prone on a failure.