According to the Wook: The character, as fleshed out in the Expanded Universe, eventually caught Lucas' eye. The director was intrigued by Vos and decided to include him in the 2005 film Star Wars: Episode III Revenge of the Sith. The character was scripted to appear on the planet Kashyyyk, the Wookiee homeworld, during the execution of Order 66, but the scene was cut before the scene was shot or an actor was cast. An animatic featuring Vos was developed, however,[23] and a passing reference to the character remained in the final film.[5]
This may be, however odd and obscure it may be, the reason for his inclusion in the CTT.