Saisoku Musou no Bkyuu Mahou Tsukai Ippatsu Utareru Mae ni Senpatsu Uchikaesu

Sky Vincent was born in a world where people are judged on magic rather than the quality of their character So it was inevitable that when his first magic testing came in and he had the weakest magic power available he was immediately disgraced by his family
Walking in the forest he met a wandering mage who informed him of the secret of his power while his magic is minuscule as it is the Null element it can negate other types of magic However while his magic isnt suitable for a few slow massive attacks it is perfect for a hundred quick little ones
Can Sky train up his magic so he can go from a laughingstock to the most powerful wizard in the world with a harem at his knees Note he totally will because look at the cover he has fricking guns just act surprised when it actually happens