Mitata grew up around the same time as X and Mitata's symbol is almost the same as Dororo's symbol, which is a ninja shuriken. He ends his setances with desu like Tamama.
When Mitata was born he had a birth defect which made him obbssesed with fighting. Mitata's Mother was worried that he would get himself killed. Instead Mitata was "play fighting" with his mother and he killed her during combat.
When Mitata went to school he had killed Tororo in an argument. He met Flarere and they fought. Mitata won against Flarere. After the fight they teamed up and killed Flarere's brothers, Dokuku and Giruru.
They both met X and Mitata beat X with Flarere's help. They were best friends. Blowing up schools, Killing bullies, they did everything!!! The newly healed X had decided to steal Kururu's base by beating him up. They named this new base the X base after X had owned it. They had a perfect base Mitata was using the holo-training program, X was watching TV, Flarere was studying engineering. Their base was hacked by a young hacker named Kerara and they tracked the signal back to Kerara and they fought him. Kerara won against them. They made a pact and the X-Platoon was made.