Nightshade

While it is said that Nightshade is Riley's sister they are not physically related. Riley is five years older then Nightshade. He was out exploring when he stumble upon her at the river bank. He knew she was not of one of the local tribes because her fur was dark. He scooped her up and took her home. His father was outrage. Wanting to get rid of her because she belong to a enemy tribe that dwells in the caves. That tribe has broken treaties and caused a lot of problems for Riley's clan. How ever Riley manage to reason with his father and was able to keep her alive. With the help of his mother Riley raise Nightshade.