@Yuki
Spoiler!
Harem and happy ending. The MC is practically a G** having defeated the actual G**'s agents. Though this isn't a strictly happy story. This world is very cruel and there are depictions of torture and murder including of children. The MC is also forced to adhere to the values of the world and kills a commoner that criticized him in front of others at the academy. He would normally have had to also kill the commoners family for the insult but he told the others in the vicinity they need to keep their mouths shut on the issue.