Gen Isyrugi is the younger brother of Isurugi Jin. Aside from Moroha, he's the only Savior in their class who can open all his prana gates; apparently, he started to practice using prana two years prior to his enrollment, explaining his advanced abilities compared to most of his colleagues. It took him a full year to open all his prana gates.
He harbored jealousy towards Moroha due to his popularity with the girls in the class, despite having roughly the same ability to open prana gates in his body. Right after defeating Satsuki, Moroha came to challenge him to a duel, which Gen ultimately lost.