I am a Godkilling Archangel

Lucifer is an angel who loves to battle and hates to lose. In the midst of a battle against the Demon Lord, he was suddenly betrayed by his comrades and sent several hundred years into the future, into a modern world where demons and humans coexist. Lucifer lost all of his power, but he learns that he can evolve by copying the abilities of his defeated enemies. Lucifer realizes that the more enemies he defeat, the stronger he becomes. Now he will seek out and confront the most powerful enemies he can find.

(Source: LINE Manga, translated)