Kushluk (or Kuclug) was a Naiman prince and a rival of Genghis Khan who later joined the Kara-Khitai, represented by the Mongols. He was best known for usurping the throne of Kara-Khitai from his father-in-law, but later defeated by Genghis Khan's forces and was beheaded.
He is portrayed in-game by a Cavalier but has superior stats and has his own unique icon. As a hero, he cannot be converted and can regenerate health (since The Conquerors). Technologies that benefit cavalry also benefit Kushluk but he is not affected by other bonuses.