Strongest Sage With The Weakest Crest GN Vol 12

The magician once known as a great sage has-in search of greater power-reincarnated himself far into the future. His new self has acquired the strongest crest for magical combat, but in an era where magic principles are all backwards, that crest is looked down on as the "crest of failure..." It turns out that evil demons were the ones who sowed disinformation and confusion about crests and magic, and now, Matthias and his party are in pursuit of a device that will lead them to a certain powerful demon!