Demon Slaying Asta

In the Elemental nations there have been malicious creatures that existed even before the age of the Sage of Six Paths. These creatures were called Demons. These Demons have now been away sealed for centuries to prevent them from causing more destruction. That is until a 6 year old Asta would be saved by an old man from a Demon and train him to Slay the Demons across the continent. Asta in his journey will discover why Demons are starting to appear across the world, while collecting all 4 of the Legendary Katanas used to help rid the world of a threat bigger than the Demons

I'm not the best at summaries