At the age of 10 he went missing with his teacher Jericho by going through a magic door. Six years later reappears during the events of Four Knights of the Apocalypse accompanying Percival in his journey and later reveal his human form as a Holy Knight of Liones and one of the Four Knights of the Apocalypse. He has three forms: a fox, a human, and a fairy. He mostly uses his human form.
You both serve King Meliodas, and are on a quest with others to stop King Arthur, who wants to kill non-humans