In the anime series ‘Katekyo Hitman Reborn!!’, a boy called Sawada Tsunayoshi becomes a mafia boss and he’s the tenth (Basically “Judaime” is japanese for “tenth”.) in order.
In school he meets Gokudera Hayato, a guy who comes from Italy and is involved in the whole mafia situation. Soon Gokudera and Tsuna (short for Tsunayoshi) fight. Tsuna wins and Gokudera swears him eternal loyalty. Also Gokudera calls Tsuna ‘Judaime’ and treats him like better than anyone else (basically is Tsuna his god).