Mitsumasa has gone through a lot of experiences in his journey to becoming Housen's general.
During his first year, he was very carefree and was constantly refusing to listen to his seniors. He was rarely taking things seriously, much to the disappointment of his older brothers.
Although his strength was badly needed in the war against Suzuran, Mitsumasa didn't step in until the last minute. Because of this, he was strongly reprimanded by his seniors for only thinking of the fun to be had in the entire situation. King Joe even forced him to sit out his supposed one-on-one match against Hana in the Monsters' Forest.
Soon after Housen's defeat against Suzuran in the Monsters' Forest, Mitsumasa began to establish his presence in Housen as King Joe's successor, but more than a few students refused to bow down to his influence.
After being told by Tominaga Toranosuke to change his recruiting methods, Mitsumasa realized that he had to build his own empire from scratch the way King Joe did to earn the other students' respects . Upon realizing this, he succeeded in doing so, even if he lost his match against King Joe .
He led Housen in the war against the Amachi Army and went only with Daisuke, Ono Teruki and Ootani Ken to their base when Miura Satoru discovered the location. It was later revealed it was a trap but they managed to beat all their army.
They were then followed by the Hana-gumi who showed up to fight but the cops arrived soon and they had to run. Mitsumasa later dealt with Miura's betrayal. They knew he wouldn't betrayed his friends for nothing so they forgave him after getting even.
As soon as he became Housen's boss, Mitsumasa became more cool-headed and a smart tactician, thus living up to his duties as the Head. Among his numerous achievements as Housen's Head include engaging in a war against The Manji Empire. Mitsumasa has also already challenged Hana to a fight, but loss.
After his graduation he passed on the leadership of Housen to his younger brother Mitsunori.
- Mitsumasa vs. Matsuo Daisuke - Won 
- Mitsumasa vs. King Joe - Loss 
- Mitsumasa vs. Hana - Loss 
- Mitsumasa vs. Maezono Satoru - Won 
- Mitsumasa vs. Anan Yoshiki - Won