Hi. I'm trying to remember a manga about a hero who kills his team mates in order to absorb their levels.

There was a girl who fell in love with the MC. He ended up killing her, and her sister/friend asked some old guy if she was doing okay. The old man said yes, but really he knew she died because of the class of the hero.

My memory is hazy from this point on, but I think there were 299 other heroes like this. These soldiers are made in preparation for the demon king's anticipated revival. The man who raised these heroes called them a name that had "garbage" in it. There was a character who wanted to join the MC, but he said she/he was worthless and didn't let them join. Said character was a mushroom shooter type magician or something.

Thanks for your help

Yakushoku Distpiari - Gesellshaft Blue

This one i think.

@Sottooshie: That's the one!! Thanks =)