Aragorn is a winged horse ridden by Brunnhilda the Valkyrie and previously owned and ridden by Dr. Dane Whitman, the Black Knight. Whitman was the nephew of Professor Nathan Garrett, who had adopted the guise of the earlier, criminal Black Knight. In this role, Garrett had ridden a horse whom he had mutated using genetic engineering techniques that he had developed. The artificial mutations gave the horse large feathered wings and other special adaptations, which enabled him to fly. After Garrett's final defeat by the original Iron Man, this winged horse escaped and eventually was further mutated and fell into the possession of the Dreadknight. Garrett, dying from the fall he had suffered in the battle, persuaded Whitman to vow to use the scientific discoveries he had usedas the criminal Black Knight for good.