He doesn't know they switched. He had planned from the beginning to use Psyche to his advantage. Her death was predetermined but because Medea and Psyche both wished to be each other it changed the Prince's plans entirely and he hadn't caught on yet. Also o.o she's not dead, I think in the raws if I remember correctly they get to her just in time.
I kinda have a feeling what will happen in the ending. And I never mentioned someone is dead. And another thing, didn't the prince got the message from the crow which was supposed to be for Heli indicating Medea's circumstances. That is why the prince planned on killing Psyche's body.
No, Medea sent two messages. One fake for the prince and the right one to Helio. So the prince doesn’t know that they switched so far
The message by crow was a fake letter for Helio that told nothing about her predicament. There is a reason the Prince is trying to kill Psyche, but it's not for that reason. He's first gonna use her death to raise his image as a pitiful Prince because someone assassinated his Crown Princess Candidate and was going to frame Medea for it I bet. He's a sadistic mofo that we did not truly see coming.
Half way through I almost dropped the story (Chapter 8 of course because of that annoying Crowned Prince). Good thing I hold onto it and continued reading.
I know he truly despise Medea, BUT WHY IS IT THAT HE NEVER HAD THE HARD TIME TO DECIDE NOR HAD SECOND THOUGHT TO KILL THE BODY OF HIS BELOVED PSYCHE (Even though the soul is different). He didn't even consider finding a way to swap back their souls. ┑(￣Д ￣)┍