Thundera was the home planet of the Thundercats, before it was destroyed by a cataclysm. Very few of the humanoid cat-race known as Thunderians escaped, but among those were the Thundercat Nobles, including Jaga, who held the Sword of Omens, and Lion-O, son of Claudis, the leader of the Thundera. Claudis did not escape, because he remained behind to assure that their ship made it off the planet safely.