Anime Quiz! Guess this anime series!?

In this anime series, the main character has left his family because he was deemed as a failure. he flees to another country where he meets the love of his life. he then continues to lead a relatively normal life working with his lover in a restaurant. sadly, his lover gets killed as a sacrifice to resurrect a certain demon. consumed by guilt, he embarks on a journey to gain more power. he comes back home years later with a new power and is suspected of killing members of his family even though he is innocent.