I'm trying to find a manga where the main character is a boy with no aptitude for magic, but wants to learn magic. He goes to a magic school despite the fact that he can't do.
His teacher looks like a magician but in reality is a fighter and has muscles. The main character one-shots the Demon Lord (who looks like a skeleton) and later there's more Demon Lords of Earth and Lightning
It turns out that the main character is very powerful, so whenever he uses a wand it breaks in half.
I found it! It's Doryoku Shisugita Sekai Saikyou no Butouka wa, Mahou Sekai wo Yoyuu de Ikinuku (AKA The World's Strongest Fighter Who Tried Too Hard Living Leisurely in a World of Magic)
One day, a martial artist named Ash was suddenly reborn into another world. He decided that he will become a sorcerer in his second life. He went through harsh training after becoming the apprentice of the former hero, Morris. Then, the "Emperor of Darkness" suddenly appeared! Right when the end of the world was approaching, he one-shotted the demon lord?!
