Question: who arya stark has killed?
Answer: On the way to Riverrun, they encounter two men on Arya's death list, Tickler and Polliver, who were both Gregor Clegane's men-at-arms at Harrenhal. In the ensuing fight, Arya personally stabs Tickler to death and reclaims her sword Needle from Polliver's corpse, but Sandor is severely injured.