This unnamed man is the father of Yohei.
Yohei's father is a large man who has blue eyes and messy brown hair with a beard. When he reappears, he is wearing a ragged white t-shirt and ragged trousers and is bare foot. He also is wearing a bandanna.
Yohei's father is very outspoken, seemingly often having inspirational speeches which his son often quotes.
He lived by the sea with his son until, one day he set out on the ocean to hunt a Kraken. After getting lost and ending up on a deserted island, he teamed up with the Kraken he sought to defeat, whom was equally as lost as he was to try and find a way back home.
True Cross Academy arc
During the battle against the Kraken, he triumphantly returns. The battle promptly ends and he explains that the Kraken was just as lost as he was and that it turned over a new leaf, the two setting aside old grudges to help each other.