The Sacrifice of Our Enmity by elizaye
Summary: In a bargain for peace between their nations, Castiel is promised to Dean, King of Laurentia. Neither one of them is pleased with this new development, but a shared sense of duty has them both agreeing to it. As time passes, they come to care for each other, and it seems that fate has given them the means to happiness by bringing them together. But all is not what it seems. Castiel's arrival in Laurentia sets in motion a scheme that has been in the making for years, a scheme that—if successful—could damage their budding relationship irreparably.
Comments: 10/10. This is amazing. It’s a medieval and arranged marriage AU. Cas is a girl in this one, and I haven’t read het porn in such a long time, it’s refreshing to read about the body parts I have. The plot is amazing, complex with scheming royals and conspiracies. It’s truly amazing and I love it. There’s some parts that are really angsty, and there’s brief major character death, but the death is not permanent so don’t worry. The sappiest ending ever, they are so happy. I love all their characterizations, especially Dean’s. Dean in fanfics are usually portrayed as emotionally stunted, but actually according to the show he’s very in touch with his emotions. The Dean in this fic is the Dean from the show, he can apologize, he acknowledges his own feelings and other people’s, and he can display vulnerability, even though he doesn’t like it very much.