After being forced to work for a criminal called the Pusher, Calvin helped Ka-Zar put a stop to the Pusher’s plans.
Calvin would later go onto murder his mother, Wilma Calvin, in an effort to continue her research into the Super-Soldier Serum. To that end, Percy lured Bobbi Morse, Mockingbird, to Atlanta, since she knew his mother early on in Bobbi’s career. He thought to capture Morse, but the S.H.I.E.L.D. agent go the upper hand and apprehended Calvin on her own.