Slayn was the Tal'darim capital world, or bladeworld. It is a dark world with a harsh environment, possessing a dry, hot climate with deadly storms. The planet is rich with terrazine, a gas sacred to the Tal'darim, that allows them to commune with Amon in the Void.
At night, it releases a terrazine fog in cycles. This fog has killed the planet's jungles.
Slayn was a jungle world, before it was settled by the Tal'darim—fanatical followers of the xel'naga Amon. After their settlement, eruptions of terrazine gas from the crust of the planet killed off the jungles, but this gas allowed the Tal'darim to pierce the veil between dimensions and commune with their god. For centuries the Tal'darim were centered around this planet, and here would invoke the rite of Rak'Shir, which allowed them to ascend the Chain of Ascension.
Fourth Ascendant Alarak was part of the Tal'darim on the planet, when First Ascendant Nuroka ordered Alarak to help him overthrow Highlord Ma'lash, as Nuroka had seen that Amon cared little for the Tal'darim. Alarak entered the Rak'Shir between the two, but at the last moment sided with Ma'lash, killing Nuroka and becoming first ascendant.
The End War
During the End War, Alarak set his plan to get revenge on Amon into motion, and allied with Hierarch Artanis and the Daelaam, leading them to Slayn. Alarak deceived Artanis into slaying Ma'lash's guardians, and then challenged Ma'lash to Rak'Shir. Though unhappy with being deceived, Artanis committed forces to aid Alarak in his fight against Ma'lash, and fought through his forces and hybrid allies to give Alarak the upper hand. Alarak eventually bested Ma'lash, casting him into the Pits of Ascension. Alarak ascended as Highlord of the Tal'darim, and committed them to the fight against Amon as revenge for his betrayal.
After Alarak's ascension to highlord, a splinter group of the Tal'darim loyal to Amon challenged First Ascendant Ji'nara to Rak'Shir. With the aid of allied commanders, Ji'nara was able to maintain her position on the Chain of Ascension.
After Amon's destruction, Alarak abandoned Slayn and left to find a new homeworld for the Tal'darim.
Slayn's climate is as merciless as the Tal'darim. It was once a lush jungle world, however, Tal'darim terrazine exposure has left the world a barren and brutal land. The climate is dry and hot, with deadly storms that roar across the planet.
The storms of Slayn are titanic in size, and commonly include pockets of intense cold and large twisters.