The Strongest Sage with the Weakest Crest 19 (manga)

Matthias and his friends head to Boseil to confront the reincarnated chaos demon Zadogilgias. Even in his previous life as the powerful Gaius, Matthias was barely able to defeat Zadogilgias. Without his fully developed magic, Matty has little to no hope of defeating one of his greatest foes. However, unlike in his past life, Matthias now has reliable companions, and with a little luck, he may stand a chance against the chaos demon!