Knight , who each struggle to balance personal lives with the hectic work and training schedules. During the first six seasons, Burke, O'Malley, and Stevens all depart the series. New young doctors in the residency program include Lexie Grey Chyler Leigh , Meredith's half-sister, who is killed with her love interest Mark Sloan in the season eight finale where the doctors are in an airplane crash. Other additions include Leah Murphy Tessa Ferrer , who departs near the end of the tenth season but returns during the thirteenth; Shane Ross Gaius Charles , who departs with Yang in the tenth-season finale; Stephanie Edwards Jerrika Hinton , who resigns during season thirteen; Jo Wilson later Jo Karev Camilla Luddington , a doctor who begins a romantic relationship with Karev; Andrew Deluca Giacomo Gianniotti , the former love-interest of Meredith's half-sister Maggie Pierce Kelly McCreary , who also serves as head of cardio; and Benjamin Warren Jason George , an anesthesiologist-turned-resident- turned-firefighter ,  who has to balance his own desire to succeed with his wife Miranda Bailey's new role as Chief of Surgery. Season eleven sees the departure of Derek Shepherd, and in season twelve, attending cardio surgeon Nathan Riggs Martin Henderson joins the show.