Origin
Arthur is the leader of the Morotari, a group of do-gooders, who modelled themselves after the knights of the round table. Arthur’s real name may or may not be Arthur, because he is supposed to be the ‘King Arthur’ of Morotari. He enlisted Jerom, Sidonia and professor Barabas in his group.
His son Odilon served years as a sidekick of Jerom until Odilon could stand on his own as an adventurer.