Having witnessed a great deal of death and cruelty for her age, Arya is filled with rage. When her thoughts are not focused on survival, they generally turn to her desire for revenge against the people who have hurt her family and friends. She is also trying desperately to take control of her life despite being repeatedly taken captive by adults. Because she is still young and small, she's not able to fend for herself, and though she would prefer to fight her enemies like a wolf, she instead often has to hide like a mouse. Even so, Arya has already demonstrated a willingness to kill, and she doesn't feel any sense of remorse when she does. On the contrary, she wants to become more skilled at it. Her behavior suggests that killing seems quite normal to her, a fact that's hardly surprising given the tremendous amount of murder and death she's witnessed.