[Demon Slayer X Honkai Impact 3] the Child Hidden by the Gods

He is a child raised by immortals and a heretic abandoned by the world. From accidentally discovering the truth of the world when he was young and being hidden by the gods, to when he unexpectedly stepped into his own world again a few years later, he found that the world seemed to have changed dramatically. The former younger brother did not inherit the family and had long since disappeared, but the successor country had an "eldest son" who was exactly like himself. The world seems to have automatically filled in the patches after its own vacancy, and the boy who changed his name to Yaelan embarks on a journey to find the truth behind all this. The ghost killing team that has been passed down for thousands of years, the ghosts hidden in the night, the cursed spirits invisible to ordinary people, the ancient place of inheritance... "Brother? Long time no see." The young man with the streaks on his forehead as red as flames looked at the familiar boy in front of him with a complicated expression. "Ah... Long time no see." "Yuanyi." Purpose: Find your true self