Inner World Aid Guide

After receiving a guide to getting help from the Otherworld, Chen Lin transmigrates to a world of anime. He thought the so-called Otherworld meant a realm crawling with demons, ghosts, and monsters, utterly unlike the ordinary world. But when he discovers that the ones asking for help are an elven princess and the knight who protects her, a snow woman who can't afford her rent, three succubus sisters who won't let anyone so much as touch a finger, a mermaid idol group, and his childhood friend from the oni clan, Chen Lin finally realizes: so that's what they mean by the Otherworld!?