Pony is one of Iron's few friends, so it's no surprise that Iron recruits him to help him out against the Syndicate. When Iron goes to visit Pony, Iron finds that Big Daddy had made it personal with Pony by cutting out his eye. Pony would have had Iron's back regardless, but losing his eye makes him want revenge all the more.
Pony has a 3.0 Strength rOid increase, with no agility increase, making him the 5th strongest person around.
Pony and his "Band" help out Iron and the Maiden when they face off against Sweet Joey Petunia and his Syndicate thugs, and Detective Manetti and the police.