Arata was forced to bear the sins of his father, resulting to him being shunned by most of society. However, even with the infamous reputation associated with his family, he continued to pursue his dream of becoming a hero. What he lacked in opportunity, he made up with passion and perseverance. Even as a young professional, he always felt an immeasurable amount of doubt from his colleagues ; frequently being labeled as the son of a criminal by the general population made things even worse.

Motivated by the frustrations he was forced to face on a regular basis, Arata eventually made a name for himself due to the numerous accomplishments he has garnered over the years. Through sheer effort and persistence, he was able to rise through the ranks of the hero community. Wanting to give back and lend a helping hand to those in need, Arata decided to establish an institution for aspiring heroes and heroines, hence Kosei was created.

Before meeting Arata and being recruited to Kosei, Mako was a professional hero in Hokkaido. Although well-versed in combat, situations that call for it were scarce. Instead, most of his accomplishments have been associated with missions relating to rescues and disaster management.

As strange as it may sound, early on in Lee's life, he secluded himself from most of civilization, investing all of his time and effort on his skills. Eventually, he realized how empty his life had been, and began wandering throughout Japan, hoping to find some sort of purpose. Given that he was away from society for a significant amount of time, what he deemed socially appropriate apparently differed from most; no big surprise there. So he frequently found himself in some sort of misunderstanding with random individuals, and sometimes, with the law. Rumors about Lee had been passed on, eventually reaching the ears of Arata. The two traveled together for a while and after a bit of convincing, Lee had agreed to take up residency at Kosei as member of its faculty.