Arla Fett is the sister of Jango fett. She was believed to be dead, but it was revealed she was actually captured by the Mandalorian Death Watch. Thinking that her family was dead, she later joined the Death Watch. She is known to have killed a couple "retired" mercinaries or bounty hunters. She was eventually captured and charged for these deaths and was deemed mentally insane. She was put in a facility on Coruscant and drugged.
She has recentally escaped with help from Kal Skirata, she is currentally being treated at the Skirata homestead by Bardin Jusik, and resident medics. ( information from republic commandos order 66 and imperial commandos 501st.)