Serve him; he is Kell of Kells.
-Grimoire Card
Yavek, Wolf Baron is a Baron of the House of Wolves. During the Reef Wars, Yavek was a minor lieutenant of Skolas, Wolf Kell who managed avoid being captured by the Awoken in the Cybele Uprising. When Skolas resumed control of the Wolves and named himself Kell of Kells, he promoted Yavek to Baron as a reward for his loyalty and sent him to negotiate with the House of Devils and House of Kings on Earth. He is encountered in the mission The Ruling House in King's Watch, where he is meeting with Paskin, King Baron and Vekis, King Baron. All three Fallen nobles are defeated by the Guardian.
Prince Uldren Sov believed that Paskin and Vekis only attended the meeting to assassinate Yavek, which would have been a firm dismissal from the Kell of Kings of Skolas' plan to unite all of the Fallen Houses under his banner. Whether or not this is true may never be known due to the Guardian's interruption.
