Seth Clearwater is a member of Jacob Black's renegade shape-shifter pack and is introduced in New Moon as Leah's younger brother and a young member of the La Push werewolf (shape-shifter) pack. Aside from Jacob Black and his sister Leah, he is the most developed werewolf in the Twilight Saga. Seth changed earlier in his life than the other werewolves, as he changed around the same time as his sister Leah Clearwater, the only known female werewolf in the series. His transformation, along with his sister's, helped Leah learn why Sam was able to ignore his love for her and move on to her cousin Emily, although she is still bitter about it. On a sadder note, his father,Harry had a heart attack, and consequently died. Although, Seth is different from the others he is friends with the vampires unlike Jacob.