Who Are the Main Characters of Warhammer 40,000?: The Xenos

This is… well, everyone else. It’s a big galaxy, and there’s more than just humans in it.
The Aeldari, also known as the Eldar, are essentially fantasy elves, but sci-fi. Now an all-but-extinguished race, this long-living species ruled most of the galaxy millennia ago with an almighty Empire of its own. Their long lives saw the Eldar pursue everything from martial prowess to creative passions, to the point that their society devolved into depraved hedonism in pursuit of ever-new pleasures—awakening the Chaos god Slaanesh out of the Warp, who feasted on the souls of the Eldar and almost wiped them out entirely. Now, their survivors roam the galaxy on giant world-ships known as Craftworlds, seeking out a home and embittered by their downfall.
The Drukhari, also known as the Dark Eldar, as also remnants of this empire, but instead of rallying to oppose Chaos, they chose to remain in the decadent ways of their former society, forming cabals of piratical raiders who roam the galaxy enacting pain for their pleasure.
The T’au Empire is a fairly nascent stellar faction on the fringes of the Imperium’s borders. Ruled by a caste-driven race called the Ethereals, the T’au Empire rigidly believes in a philosophical principle called the Greater Good: a belief that all civilizations must come together to create the greatest benefit to the greatest number of peoples… or be eliminated if they disagree. Flying giant mech suits into battle, the T’au’s forces are made up of both Ethereals and several other species that have joined the Greater Good—including both other Xenos races and human dissidents.
The Tyranids are an extragalactic, insectoid-esque hive-swarm, intent on hunting and eliminating all other life in the galaxy. Their massive hordes of interconnected bioforms are divided into massive Hive Fleets, each linked psychically through their massive biomechanical ships. The Tyranids are sometimes aided in their invasions of worlds by corrupted sleeper-cells of locals known as Genestealer Cults, who sabotage defenses and indoctrinate the populace to become human-alien hybrids, believing they serve an alien god—but largely exist to alert the Tyranids to worlds ripe for consumption, of both cultists and resisters alike.
The Space Orks are massive, green-skinned warrior-tribes who are the most populous species in the galaxy. Often dismissed as savage, idiotic brutes, the Orks and their forces—driven by a desire for the great “Waaaagh!”, a pseudo-religious crusade to seek out combat and violence—are actually a major threat to the galaxy at large, and the only reason they’ve not dominated it entirely is that often their yearning for conflict sees their myriad factions and tribes turn on each other.
The Necrons are an ancient machine race that, relatively speaking in the 40K timeline, only just re-emerged on the galactic scene after tens of millions of years in stasis. The former servant forces of the C’tan, the long-extinct oldest intelligent species in the galaxy, the awakened Necrons seek to re-establish their masters’ dominance.
The Leagues of Votann are the newest faction in 40K, making their debut in the tabletop game earlier this year. A subspecies of humanity termed “Abumans”—genetically divergent descendants of colonists that colonized worlds with radically different gravities and environments to Terra—the leagues are a loosely connected group of mining confederations made up of small, dwarf-esque clones called the Kin. A highly technologically advanced society that co-exists along with artificial mechanical beings known as the Ironkin, the Leagues roam the galaxy mining the resources of the universe, for commercial and technological gain.