Chain devils add 2 to their strength score and 1 to their constitution score.

Chain devils have non-magical darkvision for up to 60ft.

Chain devils are naturally well versed in infernal, and may learn common.

Chain devils have resistance to fire and poison damages, as well as advantage in constitution saving throws against being poisoned, but vulnerability to radiant damage.

Chain devils have access to chains for attacks. Chains are a natural melee weapon with which the chain devil is proficient in, dealing 1d6 + str slashing damage and can come from almost anywhere on their body. They cannot be removed, even by the chain devil, and are counted as objects being worn, even when being used to attack, as the chain devil doesn't need to hold the chain to attack with it. They may only reach up to 10 feet away.

Chain devils may grapple with a reach of 10ft using their chains. Creatures grappled by a chain devil are also restrained. As a bonus action, chain devils may attack a creature grappled by them for 1d6 + str piercing damage.

Chain devils are proficient in athletics due to their naturally powerful builds.