Xandros

Xandros is a destroyed world that is controlled by the Burning Legion. Little information about the world is known other than it was destroyed by Mongrethod, an annihilan.

Talador Storyline
Adventurers are sent to Xandros during the Talador Storyline alongside Exarch Maladaar and Lady Liadrin in pursuit of Gul'dan and Teron'gor. The two warlocks throw them off by summoning Mongrethod to distract them while they escape. While Mongrethod perishes in the ensuing battle, Gul'dan and Teron'gor manage to escape the usurpers' clutches, though they are pursued once more.

Respite
Sometime after the Talador Storyline, Highlord Kruul took control of Xandros in the name of Archimonde, restoring the integrity of its population. Not shortly after, the warlock Naz'groth arrived to Xandros seeking reinforcements. Naz'groth personally congregated with Highlord Kruul, pleading with the demonic commander to allow the warlock additional forces in order to assault Auchindoun. At first, Kruul was primed to execute Naz'groth on the spot. However, after reconsidering the Legion's limited options in this alternate timeline, Kruul decided to provide Naz'groth with his request, and thus, the warlock departed for Auchindoun.