"I take suffering before disgrace!! FOR COMMORAGH!"
Xylatro is seen with a fellow Dark Eldar surprising Human children and inviting them to an adventure. In truth, the Dark eldar lead them to their slave pit, cut them in half, and wear their torsoes as muppets to play with.
By the events of the Inquisition's return from the warp, Xylatro is seen still accompanying his friend to receive the Human invaders. Silent at the starts, he lets his companion get cut in half without reacting. While Xylatro appears unconcern with the horrifying fate of the Dark Eldar atomized before his eyes by Leman Russ, he does behave empathically towards the rest of his comrades: Calling people by their name, not wanting to make assumptions on how "stoked" they were by an imminent demonic invasion and of course refusing to bother them to raise their hands for a vote.
The next time we hear from Xylatro is when he is transporting Leman and the Inquisition forces towards the Arena. During the boring journey, he participates with Jebarion and Skraket in a mind game where they must guess the word Leman is thinking about. As a result of Leman's powers, what he thinks of becomes reality and the Eldars have to be quick if they don't want the deadly things Leman imagines to be the end of them. Sadly for Xylatro, one of these ends up being Slaanesh, and his cowardly comrades pass their turn to him. This betrayal prompts Xylatro to curse his brothers, and attempt to speak the forbidden name for the safety of Commorragh before the Chaos God can enter their reality. Despite his efforts to say the name out loud, Xylatro is disintegrated by She-Who-Thirsts, his soul destined to suffer for all eternity at her/his side. Also Leman was getting sleepy so he didn't hear what he said.