Sam/Cas or Sam & Cas, possibly Dean/Cas hurt/comfort, dark!fic

[dreamsofspike]

I'm looking for any fics anyone can recommend in which Sam is, for whatever reason (demon blood addiction, soullessness, anything else) evil or abusive or scary and mean and dark, and mistreats Cas, hurts him or holds him captive or uses him for his own ends, etc. Non-con, slavery, abuse all okay (even recommended ;) lol)

Anything at all along those lines, especially where there's Dean/Cas comfort to go along with it after the Sam/Cas hurt :)

Anyone? :)

Thanks :)
DoS