He is just like Vishnu who got sucked into this world through a wormhole. It doesn't happen often but when Vishnu arrived the spatial layer around the world weakened slightly and some worm holes got connected to this planet. There were a total of five people who arrived here but only Vishnu and Wang xi remained. The others are all dead.
Wang Xi himself killed two other of those people when he met them accidentally as they all spawned near the place where Vishnu first appeared in this world.
The last guy was unfortunately killed by a beast. Wang xi knows that he isn't the only one who has arrived here so he is searching for clues regarding those like him who came here. He wants to rule this planet.