AncientGreymon

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

Digimon Frontier
AncientGreymon was one of the ancient Digimon that fought and sealed away Lucemon.

Island of the Lost Digimon
Bearmon's prayer allowed both the Spirits of Fire and the Spirits of Light to become AncientGreymon and AncientGarurumon to fight Ornithmon.