The Strongest Sage with the Weakest Crest

The Strongest Sage with the Weakest Crest summary: Magic in this world is determined at birth by "Marks"—four symbols that indicate a human's magical abilities and potential. Despite being an accomplished sage, the protagonist despairs when he learns that his mark is unsuited for battle and only useful for augmenting other forms of magic. He decides to reincarnate in the far future, hoping to achieve the mark of close combat that he longs for. As reincarnated six-year-old Mathias Hildesheimr, third son of a duke's family, he finally attains the desired mark. However, he soon discovers that the world has regressed in terms of magical knowledge and swordsmanship. Basic spells have been forgotten, and only poorly crafted magic equipment is available. To compound matters, his once-praised mark is now seen as the worst of them all. Despite these challenges, Mathias displays unrivaled swordsmanship and earns a place in the prestigious Second Royal Academy at the age of 12. He defies expectations and makes waves at the academy and beyond. Meanwhile, Mathias begins to uncover sinister forces at work in the shadows. With humanity weaker than ever, he must take on the responsibility of stopping their dark plans.