The Strongest Sage with the Weakest Crest 05

In this manga adaptation of the popular light novel series, the world's strongest sage will stop at nothing to get stronger...not even reincarnation!Once the world's most powerful sage, reborn Matthias has gained the optimal crest for magical combat many thousands of years in the future. But with magical knowledge at an all-time low in this new era, no one recognizes his crest for what it is, and it will be an uphill battle for the twelve-year-old sage to prove his greatness to everyone! It turns out that evil demons were the ones who sowed disinformation and confusion about crests and magic, and now, those very demons seek to invade the capital and destroy all humans who know this secret.
Matthias still doesn't have the powerful spells and physical abilities that he did prior to his reincarnation, but it's time to use his wits and creativity to take down the mighty demons!