Kotomine Shirou, who has traveled twice, is the adopted son of Gilgamesh and Kotomine Kirei, and possesses a cross-world travel system. In order to break free from the shackles of the moon's singularity and protect those around him, he traveled to the magical world of Fairy Tail. The fusion of Moon Magic and Bajiquan uses the magic system to quickly become stronger. You meet Lucy by chance, get to know Natsu, step into the Fairy Tail Guild, and start a counterattack adventure that sweeps away powerful enemies and subverts the magical world.
I quite like it.