I want to find a manga that I read last year with this storyline:

A manga that tells the story of a hero who was fired/kick out from his party due to the cruel way he went about his work. He then met a former demon leader  who was kicked out from the devil lord castle and got bullied by his troops.

The main character have a white hair
And Heroine  I don't remember too much  maybe having long black hair with glasses