The MC is weak.. so weak that even if he is level 50, his stats is actually an average level 30's stats. There is still no Hero (the cheat Hero) so far and MC is focusing on strengthening other.
MC won just because he exploit all his game knowledge and his skill moreover the MC actually "reject" the plot armor the world giving him to proceed the scenario like the actual game (you know, just like this Demon fight). Its funny that MC actually using some already mentioned weapon to defeat the strong enemy.
The latest WN is where the MC met the Prince of Light (the strongest person in the game) and actually punching him in the face. lol