ARIFURETA - FROM COMMONPLACE TO WORLD'S STRONGEST: THE MIRACULOUS MEETING AND THE PHANTASMAGORICAL ADVENTURE

After returning from the Sunken Ruins of Melusine, Hajime decides to take Myu on one last adventure before they part ways. However, the trip ends up being much more dangerous than they expected. Hajime and his party is transported to a mysterious ruined city, where they meet and join forces with the Liberators, who were also transported here from the past. They work together to return to their original worlds. — Description from AniList community (anilist.co).