Thief (シーフ Shīfu) is recruited by Beelzebub for his expertise at stealing and his great wisdom. He often fights with Beelzebub for turns to drive the tank.
He is a wise demon who lives in Sand Land, a barren wasteland inhabited by humans and demons where the supply of water is controlled by a greedy human king. He lives in the demon territory ruled by the demon king serves as the royal adviser to Prince Beelzebub, he often helps the prince to Beelzebub tries to live in relative harmony with the humans: although he regularly steals water from them, he only takes as much as he and his fellow demons need to survive. They eventually join Sheriff Rao in his quest to find an elusive lake which will possibly meet the needs of the inhabitants of Sand Land. In search for the long-lost lake, the trio confronts the king's army several times and discovers the truth behind many mysteries. Out of all the prince's minions Thief was recruited due to his expertise at stealing and great wisdom the old sheriff his enhanced sight and demonic strength to fight against the king's army and bring down the tyrannous human king.