Amartía has made it abundantly clear that he hates [b]all[/b] gods. (Except Jvan) Sin has long since known that Xerxes would be the site of godly hate, but this only proves his point, and all you gods are only lowering yourselves to his level. Gods meddling knows no bounds, and now he has an opportunity to preach that to the rest of the world. 

Well, I know what I'm going to to if Amestris is destroyed. He hitting godhood to.