Swordsman: the Devil's Fantasy Adventure

In a fantasy world dominated by four demon kings, humans coexist with various mysterious races. The North Demon King, a gifted but arrogant genius, unexpectedly won the throne, but became an outlier among the demons because of his kind heart and fondness for humans. His life becomes hilarious with the addition of an amnesiac elf girl. When a forbidden love quietly sprouts, the North Demon King decides to embark on a journey to find the elf girl's past, but he does not know that this journey will be full of unknown adventures and challenges.