John Butkus (aka Anim8rJB) is a Canadian video game animator and designer who is currently employed by Bungie Studios. Butkus was born in 1976 in Toronto, Ontario, Canada. He was hired by Bungie in 2003 and has worked there as an animator ever since. Not much is (definitively) known about him, though his Bungie.net profile is extensive.
He was credited as an animator for Halo 2, and still worked at Bungie to work on Halo 3.