Thelestes, called The Velvet Blade, is a spirit of murder. Originally from Mabar, a feud with other powerful spirits of the plane forced her to flee to Eberron, where she found allies in the Lords of Dust. She believes that the Overlords can grant her the power she needs to defeat her enemies in Mabar, and she is in no rush to return home.
She has allied herself with Eldrantulku, the Oathbreaker, and his prakhutu Kashtarhak, the Voice of Chaos. She doesn't only work for them, however, and frequently lends her skills to the schemes of the other members of the Bleak Council, providing they don't conflict with her own objectives.
Thelestes is a master of deception and can wear any face that suits her purpose, though she has a preference for taking the form of an elven woman. She maintains cover identities in House Phiarlan, House Thuranni and most of the criminal organisations in Khorvaire. She is particularly gifted at disguise, and though she is not a Rakshasa, her disguises still hold up under magical scrutiny. She often performs assassinations for these groups, as she is a spirit of murder and relishes in it, even if it doesn't serve the interests of the Lords of Dust.
Murder is Thelestes' personal joy, not simply killing. For her, the preparation, intelligence gathering, and deception involved in her work is just as important as the actual death. She takes pleasure in the plotting, and the careful, calculated destruction of others. Adding to this, she is ageless and immortal, she has slain Dhakaani emperors and laid dragons low. She is pragmatic, leaving someone alive whom she eventually plans to kill if they are more useful to her alive; she has time to drag out the chase for decades if she needs to. Sometimes, she is satisfied to let her prey know how close they came to death, and let them go.