AncientGarurumon

From the Digimon Fontier series, AnicentGarurumon is an Ancient Beast Digimon with the power over light. He was one of the Ten Ancient Warriors that saved the ancient Digital World from Lucemon's treachery. In this battle, he and AncientGreymon endured until the very end. Prior to the said battle, he and AnicentGreymon fought another monster, Ornithmon & sealed it. The power AncientGarurumon possessed now lives on in Koji, who wields the Spirits of Light created by AncientGarurumon.

Digimon Frontier
AncientGarurumon only appears as a shadowy figure in episode 38 of Digimon Frontier when the Digidestined are informed about the history of the Digital World.

Revival of the Anicent Digimon
Bearmon's prayer allowed both the Spirits of Fire and the Spirits of Light to become AncientGreymon and AncientGarurumon to fight Ornithmon. The two ancient Digimon are finally able to destroy the powerful evil Digimon once and for all.