Seibetsu Bug ga Hasseishimashita!?

Synopsis

Yousei Sakima is a first-year high school boy who loves games. He is a pushover who always tries to please other people and has a hard time saying no. So he often has to rely on Karen Minatsuki, his schoolmate, for help and support. One day, a loud thunderclap rings through the school, and Sakima wakes up to find himself transported into the world of his favorite game, "Mirage Universe," along with Minatsuki. And due to a game bug, Sakima and Minatsuki have switched genders!? (Source: ciao, translated)