Zeno is Zatch's twin from the mamodo world. While Zatch is kind-hearted, Zeno is evil. Zeno hates his brother so much because Zatch inherited the Baou power from his father, the king and a thunder elementalist. Zeno, however, received nothing and therefore had to undergo really hard training.

Zeno's partner, Dufort, was like how Kiyo was in the beginning, and really would be meaningless if it wasn't for the fact that Zeno needed a partner to read his spells. Zeno's attacks are similar, but not exactly the same, like the spell Zatch has that shoots an electric dragon, Zeno has one that summons a wired five point object that shoots a beam of lightning the same size as the dragon.