Son of King Gundam II and King of the Britis Kingdom. Perhaps because there haven't been any major battles since the birth of the new Suda Doaka World, the Knights of the Round Table aren't even at full strength. He has also entrusted the role of renewing contracts with mythical beasts to the two princes who will lead the next Britis Kingdom, and will now watch over them.
Guided by the Crimson Knight Sinanju, King III was ambushed and defeated by the Black Knight Banshee, who had infiltrated Britis Castle, and his royal powers were stolen by the evil dragon of the underworld, X Soul.
King III, stripped of his royal powers, remains in a deep sleep. To halt the progression of his decline, the Priest Knight F90 Junior cast a petrification spell upon him.
King III was resurrected by the power of a new Holy Grail bestowed upon him by the Guardian God Sunborn. Although he regained his powers, he decided to abdicate the throne to his son and retire after this battle.