Mugen Maryoku no Isekai Kikansha

The Fastest and Strongest Dungeon Conquest by a Returnee from Another World Begins!! Yuzuru Masaki, a young man who was swept up in a mass summoning to another world, made a tremendous contribution to the five-year campaign to defeat the Evil God. Once everything was over and he wished to return to Japan from that other world, he returned to a peaceful daily life alongside his comrades who also wished to return—or so he thought. However, a few months after their return, monsters and dungeons from the other world suddenly appeared on Earth! Amidst the chaos and screams, Jo realized that the unique skills he had acquired in the other world—[Infinite Magic Power] and [Magic Power Transfer]—could still be used in the modern world…!? A fantasy tale of unstoppable dominance in modern-day dungeons, powered by the fastest and strongest leveling! (Source: Hobby Japan, translated)