The first time the revenant takes a critical hit, it is treated as a normal hit. When this occurs, its lower spine is severed. This reduces its speed to 20 feet and it can no longer make slam attacks. The revenant's legs wander off somewhere and are harmless.

The Revenant has an extra +6 to dodge attacks

Damage Resistances cold; fire; bludgeoning, piercing, and slashing damage from nonmagical weapons

Damage Immunities poison
Condition Immunities poisoned

Darkvision 120 ft.

Passive perception 12

Abyssal and Common

Mulitattack. The revenant makes two punch attacks.

Punch. Melee Weapon Attack: +5 to hit, reach 5 ft., one target. Hit: (17) 3d8 + 4 bludgeoning damage.

Rocket. The revenant fires a rocket at a point up to 120 feet away. Each creature within 10 feet of that point must make a DC 15 Dexterity saving throws, taking 22 (5d8) piercing damage on a failed save, or half as much damage on a successful one.

Guided Missile (Recharge 5–6). The revenant fires a guided missile at a creature it can see within 120 feet. The targeted creature must make a DC 15 Dexterity saving throw. The missile explodes on a failed save. On a success, the missile does not explode but continues flying: the targeted creature must repeat the saving throw at the start of the revenant's next turn. The missile does not continue flying a second time, and explodes regardless.

An exploding revenant missile deals 22 (5d8) piercing damage on a failed save and half as much on a success. Creatures within 10 feet of an exploding missile must also make a DC 15 Dexterity saving throw and take this damage.