Laer

The Laer were a xenos species originary from the world of Laeran. They were a serpent-like species that worshipped the Chaos God Slaanesh. They became extinct during the 31ºst millenium, at the hands of Fulgrim and the Emperor's Children Astartes Legion. Not to be confused with the Sslyth. And yes, GW made two snake-like aliens with multiple arms and expected nobody to notice.

Biology

The Laer had a phisiology similar to snakes, with elongated and reptilian bodies, muscular thoraxes and ofidian-like heads, with insect-like pairs of eyes and very flexible jaws, sometimes used as weapons in times of war. They also dislpayed two pairs of arms. The Laer were very fond of genetic engineering, and their society relied heavily on particular individuals modified after birth to fit certain roles. As such, it was very frequent to find wildly different laer: some with wings, some with gills and fins, some extra big as soldiers... Their displays of genetic fuckery were so impressive that Fabious Bile became inspired by them, and started making new Astartes organs based on what he learned from them.

History

During the Great Crusade, an expeditionary fleet of the Emperor's Children discovered the Laer species on the planet of Laer. And just one planet. Apparently, even though the xenos were highly technologically advanced and quite capable of space travel, they didn't have more than a single planet, their homeworld. Assuming they would be easy targets, imperial forces attacked the world, and were inmediately curbstomped. In fact, the fight against the Laer was so difficult that many imperial authorities considered offering the Laer the possibility of becoming a protectorate, so that they could learn from their tech (though, in all honesty, it was mostly to gain some time before consolidating their forcs and exterminating them). The Primarch Fulgrim, hearing this, became offended and swore to kill the xenos vermin himself, and so he launched his legion against the aliens. After a brutal and surprisingly long fight, the laer were beaten, the last of the species fighting to the last snake defending their temples.

Slaanesh Worship

It is known that the Laer practised the worship of the Chaos God Slaanesh, having massive temples dedicated to it, where they practised all kinds of rituallistic orgies and many other dark acts of absolute depravity. The places were so corrupted that just watching them made people fall to Chaos. It is in one of these temples where the Blade of the Laer was found, a ritual weapon possessed by a daemon. It was this sword the one item that started the corruption of Fulgrim during the days before the Horus Heresy.