The Strongest Sage with the Weakest Crest

It's a world full of magic, the powers and future of a mage are predetermined at birth through so-called "Marks". An incredibly skilled sage with unsatisfied Marks decided to reincarnate thousands of years in the future, reborn as Mathias Hildesheimr with his desired mark. When Matthias turns 12, his unparalleled swordsmanship has ripples both inside and outside the academy. However, the ex-sages reveal signs of a dark force working in the shadows, and with humanity weakened more than ever, it's up to Matthias to thwart their evil plans.