Isekai Kaeri no Yuusha wa, Dungeon ga Shutsugen Shita Genjitsu Sekai de, Influencer ni Natte Kane wo Kasegimasu!

An ordinary high school student's life is abruptly upended when he is suddenly transported to another world. Rather than succumbing to the overwhelming circumstances, he dedicates himself to growing stronger, steadily raising his level until he achieves unparalleled power. Ultimately, he confronts and successfully defeats the Demon King, fulfilling his destiny by saving the entire realm. Having accomplished his monumental quest, he makes the decision to leave his heroic life behind and return to his original world, carrying with him the ultimate status of a supreme warrior. However, his homecoming does not bring the peaceful normalcy he anticipated. The Earth he returns to has fundamentally changed during his absence, as mysterious "dungeons" have inexplicably manifested across the modern landscape. Thrust into this altered reality, the former hero must adapt once more. Armed with the unrivaled abilities he forged in another realm, he steps forward as a warrior once again, plunging into the depths of these newly formed labyrinths that now scar his own world. This modern dungeon fantasy follows his extraordinary journey as a seasoned champion navigating a transformed society, blending everyday contemporary life with thrilling subterranean exploration.