The Oracle who canonized Silverclaw wants a more absolute type of revenge. Like, Silverclaw's head on the end of a legendary sword. She's willing to pay for the job done right. And if Cage will kill Silverclaw, she'll make Cage into a Hero.
Becoming Hero is all Cage ever wanted, but he's never murdered before. He can have his dreams at the price of blood on his hands. And hey, why not? There's no reason an old were-squirrel can't learn new tricks…