Watch The Demon Sword Master of Excalibur Academy EP06 : https://anime4you.xyz/episodes/the-demon-sword-master-of-excalibur-academy-1x6/
Following a millennium of being sealed away, a terrifying demon lord resurfaces but to their astonishment, they are reincarnated as a mere ten-year-old kid. Placed under the care of the girl who unsealed them, Leonis, who was formerly a dominant demon, must adapt and endure the hurdles of Excalibur Academy.