I don't know if it's just me but the mood difference between the usual over the top hijinks at school and the cute and soft-spoken relationship with Rin just feels a bit jarring. Maybe it's because of that but the relationship feels kind of fragile and it's difficult for me to fully get behind them and enjoy the fluff
Chapter 25 changed everything. I don't think we will ever see a professional assassin drive a truck and run over some delinquent high school girls ever again.