Poseidon

Poseidon (Neptune) is the father to Zirraccu and Inyucashi Gogyu. He trains them, along with the other members of the Rokusen, to fight off against the Akkisen, led by his nephew, Akki. He is obviously, Akki's uncle, and is also the uncle to Yomi, who is on the side of Akki, and K, whose part of the Rokusen and his other nephew. Other than Hades, his other brother is Zeus. His age is unknown.