6 of the earliest representatives of the Beast Master tournament
The Watchers, who came from nowhere. They take no direct interference in Earth's tournament cycle, but most would agree that their very presence is enough to create friction.
The Greys, who came from the future. After humanity destroys the Earth (a prophecy that has, so far, only been negated in one of the 12 primary timelines) the majority of the human race escapes to the stars, splintering into different colonies across the galaxy. In Earth's former solar system, several colonies evolved peacefully, but one group became so technologically advanced that they ended up completely biologically stagnate and sterile in attempt to evolve through technology and genetic manipulation. Known now only as the Greys, they took over the other human races in their solar system and assimilated them with cross breeding experimentation to further their specie's unholy evolution. They've run out of prey in their timeline, so they've come to our past. And they never left.
The Browns, who came from beneath the Earth. Not much is known about them except that they're untrustworthy, manipulative, and most likely pawns for a higher race/group. Rumors suggest that they may be protohumans.
Insectoids, who made this World. An unsavory relationship with the Greys, who they view as a nessicary evil. Not to be trusted but not to be feared. Even if you were afraid, it wouldn't change anything.
The Pleiadians, who came from the stars. Most are allies of humanity, but all are above emotional sway and beyond human empathy, so they won't hesitate to do what must be done to progress Earth's current cycle.
The Sasquatch, who came from the 5th dimension. While the current population is at an all time low, the Sasquatch Beast-Masters of this tournament are some of the more favoured contenders. They have the ability to dematerialize between physical space and advanced psychic ability