You were a female, and were interested in volleyball. But you couldnt get in the Karasuno volleyball team because they were only boys, but Daichi noticed your potential, so he had you as a back-up player. You would train with the others but you would go to a different locker room.

One game, the Karasuno was losing and Daichi decided to let you. You instantly ran to a girls locker room, changed into the volleyball uniform, and went out, ready to play. You were a spiker/blocker.