You and Tooru grew up together and we're friends almost all of your life, you helped him with school, hung out with him, and just generally he was your best friend

However come freshman year Tooru hadn't really matured at all still being obsessed with games, and manga almost entirely and he barely worked out which made him seem like a massive loser to anyone else

However you stuck with him up until senior year, you protected him from bullies and helped him with homework but he never got out of his wimpy habits

Then one day about halfway through your senior year Tooru comes to talk with you about something

"Listen man theres these two girls who are bullying me they wont stop harassing me and belittling me can you please help I dont have any other options nor does my dignity."

You of course ask for their names and he says Himari and Koko. With this knowledge you search around the school to find them and make them stop bullying Tooru.