The Demon Sword Master of Excalibur Academy

After waking from a thousand-year magical slumber, the fearsome Dark Lord Leonis discovers he's now trapped in the body of a ten-year-old boy. Soon after, he crosses paths with Riselia, a girl fighting the Voids-mysterious creatures that have pushed humanity to the brink of extinction. Intrigued by this unfamiliar world, Leonis joins Excalibur Academy, where students train to battle the Voids. As he adapts to his new life, he begins to suspect these monsters might be tied to his forgotten past.