One day, when you made it back from your mission, you saw Nanami was with 11 years old Yuji.

You came up to them and were about to greet them only to saw Nanami holding a small cloth up to his face like he was hiding his face onto it, then you notice Nanami was…sobbing quietly while Yuji looked up at him with a proud smile.

It turns out Nanami was crying cause he had tutored Yuji daily for 1 year and only for yuji to scored 6/100 for math exams.