The setting is a world were everyone has a class at birth, people have different status or given a job base on the class. The mc has the hero class but is forever lvl1, but when people die around him he gains their levels for the fight.
I know what manga you are talking about but I forgot the title. The MC was a photographer but he and a bunch of other people with the hero class volunteered to kill the demon lord and he is stuck at level 1 because he can't gain experience when he kills his teammates to gain levels to kill monsters
The MC of Yakushoku Distpiari - Gesellshaft Blue was once a photographer who took pictures of warfare including corpses and was famous for it.