Kaiu

Known as the "builder of ships and armor".

When Hida first wanted followers, Kaiu stepped forward with Hiruma and Kuni.

To prove themselves they had to enter the Shadowlands and kill Oni no Hatsu Suru a guardian left behind by Fu Leng.

Kaiu's part in the fight with the oni was crafting the weapon Chikara which was wielded by Hiruma and later became the Ancestral Weapon of the Crab Clan. Kaiu was badly wounded by Hatsu Suru in the fight protecting Kuni, but survived.