Sakong Lu Chu is the younger sister of Sakong Yue, Shen-Ji's wife. Info about the family is on the page Sakong_family_members.
Lu Chu is a bit headstrong and independent, but is starting to show that she can handle herself. She has some reasonable outdoor-type skills and some sneaky talents, but has likely gained other talents given her more recent activities.
After that, she joined the Bearers_of_Swift_Response for a short time, during which the Imperial Warlord was trying to use her as leverage against Shen-Ji, but she is now a priest of Kalkin, allowing him to freely travel to the Empire.