Ryudamon is the partner of Masuken Kana, and was originally a Samudramon. However, he was defeated by DexDorugoramon, and reverted to a Digiegg. After temporarily Death-X digivolving into DexDorugamon, he was reborn as Ryudamon, who called Masuken "master". He would later become Hisyaryumon, and later Owryumon.