When the sentient Cosmic Cube named Kobik first came into existence by the hand of S.H.I.E.L.D. and manifested in the form of a scared child, it used her power of omnipresence to secretly seek the clone of the original Red Skull. The Red Skull once had in his possession a Cosmic Cube that was eventually shattered by Captain America. When S.H.I.E.L.D. used one of its fragments to create Kobik, its connection with the Red Skull passed on to Kobik. The Red Skull took advantage of Kobik's naivety to indoctrinate her in the ways of Hydra behind S.H.I.E.L.D.'s back. The Red Skull then executed his greatest scheme, and had Kobik turn Captain America into the best version of himself, which for Kobik, entailed he had to be loyal to Hydra. To this end, Kobik used her omnipotent powers to create an alternate timeline in which Steve Rogers was proselytized into Hydra when he was a kid.
Current Version:
Hydra Supreme
Former Versions:
Captain America (Hydra)