He was paid by Katrana Prestor to find and kill Varian Wrynn. Vendellin flew with his dragonhawk mount to the Wetlands and encountered Varian's company including Broll Bearmantle, Valeera Sanguinar, and Thargas Anvilmar. When he saw Valeera, he cast upon her the Mark of Kathra'Natir, a powerful corrupting curse. He then summoned a huge doomguard to fight Broll and Thargas while he battled Varian himself. Eventually, his doomguard was torn apart by Broll's roots and Vendellin was beheaded by Varian. However, Valeera remained cursed with fel runes on her hands.
- Vendellin appears to be wearing the Malefic Raiment.
- "Can you feel that, child? Fel energy. You've already tasted what I can offer, haven't you, and found it sweet? Yes, I can feel your desire. And I am merciful. You shall have what you crave."
- "I cast upon you the Mark of Kathra'Natir! May you gaze unending into the dark heart of the Twisting Nether!