The boy gets a notification demon lord system activated first quest be killed 1000 times and it's completed reward you got demon god aura any demon of lower than king will fear.

But our mc name akuma says now I want everyone to kneel before me and releases his aur of demon god and the shadow figure says what is this aura and soon he is destroyed then our mc gets up and sees where he is the room is full dark slowly with support of walls he moves and find knob after rotating a door opens and our mc with that goes out .