Brocko is a 2011-introduced and cartoon-only character. He is a werewolf and a student at Monster High. He used to attend Crescent Moon High before the school merged with Monster High and though the transition wasn't easy, no one would consider him and his fellow werewolves not a part of the school these days.
Not much is known about Brocko's personality, except that he harbored some ill-will feelings towards the vampires of Belfrey Prep at the start of "Fright On". Since then, he seems to have accepted Monster High's tradition of bringing monsters of all types and backgrounds together in harmony.
Nothing has been confirmed, but among the werewolves transferred from Crescent Moon High to Monster High is a werewolf girl with skin and hair color identical to Brocko's. Only their eyes are not a match, being different in shape and color. It is possible that the two are siblings, maybe even twins.