Call Between Two Realms: Grandpa Kai Gave Me a Clairvoyant Eye

On the surface, I live an ordinary life, but behind my back, I have a grandfather who claims to be emperor in another world. He gives me the ability to start with clairvoyance and end with invisibility. Others cheat and ask for money, I cheat. . . There really is a grandpa, until I was invincible in the city - grandpa just said lightly on the other end of the video, "My dear grandson, this country is actually for you."