Summary:
Magnus is a mage who always got yelled at by the Hero because he was deemed "useless." One day after getting fed up with his party he left, and upon leaving he met a merchant that sold him a mysterious book.
"Kouryakubon" wo Kushi Suru Saikyou no Mahoutsukai: "Meirei Sasero" to wa Iwasenai Oreryuu Maou Toubatsu Saizen Route chapter