The Xiaverse has been host to several extraterrestrial species over the eons. These have variously treated our world as an experiment, a preserve, and as the home of potential friends. Fortunately, they've all respected our independence. Below is a list of those already known to have visited.
- Children of Nelvaa: Described as Bear-men, they grow to ten feet (3.1 meters) high and have dark hairy bodies. They communicate via high pitched sounds that are interpreted by the human brain as psychic messages.
- Imhand: Look identical to humans, but their brain is in their chest and their head can regrow. They are immortal unless their bodies are ripped in half or burned.
- Marina: A product of the matter and energy revolving around a black hole, this being has amazing control over time and gravity and has the ability to manipulate the form and color of her body. She may be unique in the universe.