Noroma Mahou to Yobareta Mahoutsukai wa Juuryoku Mahou de Musou suru ~Mada Juuryoku no Gainen no nai Sekai nite, Shounen wa Banyuuinryoku no Ou to naru~

Wade, a boy born in the slums and raised by terrible parents, finds a glimmer of hope when he becomes an apprentice adventurer. Enduring grueling training, he’s promised to be taught magic if he perseveres. On the day of his fateful magic instruction, while others are granted promising fire and water magic, Wade receives what seems like the worst of luck—a magic called “Slow Magic.” In despair upon realizing it’s a spell that makes him clumsy, Wade recalls memories of his past life as a corporate s*ave. “Huh? ‘Slow Magic’? That sounds like gravity magic, a powerful spell!” Yes! In this underdeveloped world, where the concept of gravity is largely unknown, Wade is underestimated. Determined, Wade faces his newfound gravity magic head-on. Increasing his own weight boosts his attack power, while being lighter makes him more agile. He can even float lighter than air and pseudo-create objects by manipulating gravity’s focal point. Thus, despite ridicule, Wade uses gravity to overcome those who mock him, defeat goblins, and even topple boss monsters. Teaming up with a fellow unpopular magic user and a boy aspiring to be a hero, Wade delves deeper and deeper into dungeons in search of thrilling battles against the strongest foes.