Kaiza was a travelling fisherman who came to the Land of Waves to seek new opportunity.
After saving Inari from drowning, he taught the boy everything he knew about life, stressing that he must protect the things that were precious to him, saying to always do so "with these two arms". He eventually married Tsunami, Inari's mother, and became Inari's stepfather as well as role model. When Gatō tried to take over the Land of Waves, Kaiza tried to stop him. But Gatō decided to use Kaiza to scare anyone who hoped to stand against him. To do this, he had his bodyguards cut off Kaiza's arms (in anime Kaiza's arms were not cut off but badly injured) mocking his statement of "protecting the things you love with both arms" and then executed him in public, scarring Inari, who was watching the execution.