A Jedi Master during the time of the Clone Wars, he appears in the book Yoda:  Dark Rendezvous as a Jedi released from the clutches of Asajj Ventress to carry a message from Count Dooku to Master Yoda.  Apparently he is without an apprentice at this time, since he acquires a new apprentice from the Jedi Apprentice Tournament.  His new apprentice, Tallisibeth Enwandung-Esterhazy, otherwise known as Scout around the Temple, accompanied him, Master Leem, Master Yoda, and Master Leem’s apprentice Whie on a mission to talk to and possibly take Count Dooku into Republic custody.  This failed disastrously when Ventress intercepted their transport, which was full of civilians as they were trying to get to Dooku as undercover Republic agents.  When Ventress boarded the ship with Trade Federation assassin droids, this became impossible.  After having already faced Ventress ealier, Maruk was forced to face her again, after already having dozens of cuts from a hard fight with the droids, who killed Master Leem.  In the short duel that followed, Ventress easily disposed of Master Jai Maruk, who became the 18^th Jedi that Asajj Ventress had killed up to that time.