Trying to find a Demon Spencer Reid Criminal Minds/Supernatural Fanfic

It has been quite a while since I read this and I can't seem to find it anywhere. I remember that Spencer was a Demon and I think it took him a really, really long time to break in hell. I think he was super old and was a little OOC. He helps Sam and Dean with some cases and I think it takes a while for Dean to warm up to him.

Honestly I can't remember much besides enjoying it and at this point I'm open to any Demon Reid fics.

Thanks for any help and recommendations!