Multiattack. The gray render makes one Bite attack and two Claw attacks.
Bite. Melee Weapon Attack: +8 to hit, reach 5 ft., one target. Hit:17 (2d12 + 4) piercing damage. If the target is Medium or smaller, the target must succeed on a DC 16 Strength saving throw or be knocked prone.
Claw. Melee Weapon Attack: +8 to hit, reach 10 ft., one target. Hit:13 (2d8 + 4) slashing damage, plus 10 (3d6) bludgeoning damage if the target is prone.
Bloody Rampage. When the gray render takes damage, it makes one Claw attack against a random creature within its reach, other than its master.
A curious impulse drives the gray render. Despite its hulking form and terrible appetite, it wants most of all to bond with an intelligent creature and, once bonded, to give its life to protect that creature. Great strength and a ferocious nature make gray renders fierce guardians, but they lack a shred of cunning.