Who do you think has the sadder backstory?

I would honestly say Silver. Shadow at least has happy memories to latch onto. He can remember a time where life was good,before the raid on the Ark. Silver doesn't have that. He was born during the end of the world and the thing responsible for it can't be permanently killed. The only life he's ever known is one where he has to fight a fire demon every single day to survive,with only one other person to talk to and the entire planet is nothing but flames and ruins. Then eventually,just like Shadow,he also loses the only friend he's ever known.(For awhile anyway)