Sabellian, because he will see it coming long before Wrathion even thinks about it, and has set up the field so when the day comes Wrathion doesn’t even know what happened until it is all over. He is probably already prepared and just waiting for the whelp to fall on his face.
Oh look after decades if not centuries, one of his confidants switched sides and now sits at Wrathion’s right hand. How convenient. Let’s also not forget the netherdrakes are MIA thus far in this expansion and they are Sabellian’s responsibility.