Halfling Immortal

Mori is just a gloomy boy trying to survive the whole teenage drama that comes along with being a high schooler. But when he gets himself entangled with a quarrel between a strange couple on a school trip, he gets a shock of a lifetime. With one claiming to be his grandson, while another claiming to be his great grand disciple, they send him into a world of warriors and deities, of crafts and curses, where the flabbergasted Mori finds himself inside a body of a 2-year-old boy who was prophesized to ruin the nine paths of the Earth and sever the three Heavens!