I'm gonna make a wild assumtion that the Medea on the cover isnt actually her but Pyche in her body. After they switched bodies P becomes more like M and eventually orginal M discovers the prince's true colors and intends to use P to get rid of him. So they team up but P having learned from the master, OG M, out smarts her and P becomes wicked and betrays OG M. And Helios, could end with two possible endings, he might fall for P and betrays OG M or he dies for M. Either way he won't be end game. There's nothing to prove or point to any of this but I just liked the idea of the niave child turning wicked.
Honestly dont want Helios to end up with P tho