Who was Renee Walker's mentor?

Renee Walker's mentor was Jack Bauer. Jack was a legendary figure in the Counter Terrorist Unit (CTU) and had been working there since the beginning of the series. He was an experienced and highly skilled agent who had been in the field for many years. He had a long history of successful missions and was looked up to by many of his peers. He was also a mentor to many of the younger agents, including Renee Walker, who he took under his wing and taught the ropes of being a CTU agent. Jack's guidance and support of Renee enabled her to become a strong and successful agent in her own right.