Saijaku Boukensha ga "Kanzen Drop" de Gendai Saikyou: Jibun dake no Rare Skill to Custom Ability wo Kushi shite Hoka no Dare yori Tsuyoku Naru

A mysterious dungeon has appeared in this modern era?! Adventurers challenge this dungeon in the pursuit of their dreams of getting rich quickly. From the weakest to the strongest! Aiming for the top by leveling up! The more you fight, the stronger you become in this battle saga!

(Source: Square Enix, translated)