Shikkaku Mon no Saikyou Kenja

His strength being limited by the magic crest he was born with, Mathias, the world's most powerful sage, decides that reincarnation is necessary to become the strongest of all. Upon his rebirth as a young boy, Mathias is thrilled to discover, on his very first try, that he was born with the optimal crest for magical combat! Unfortunately, this world has extremely low standards when it comes to magic, and everyone thinks he will always be doomed to fail.