When Himura was younger, before the events of Season 1, he was in a car crash that killed his parents and sent him into a coma. While in the coma, he is transported into the Digital Underworld, where he is attacked by a wild digimon and loses an eye. He is saved by Kotori, a tomboyish girl who ended up in the Underworld after being pushed down some stairs, and her partner Seadramon, who was once the MetalSeadramon of the Dark Masters. He also meets Inumon, a servant of Anubimon, the ruler of the Underwold, who later becomes his partner. They fight Basilikmon, a digimon who is trying to usurp Anubimon's throne, but before they can defeat him, Kotori is killed. After the battle, Himura is sent back to the real world and wakes up from his coma, only to find Inumon waiting for him. He lives with his grandparents and his younger sister, Yui.
He and first meets the Tamers during the Pharaohmon incident. Later, he gains the power of Byakko, giving him ferrokinesis (magnetic powers) and the ability to transform into Himakko.