To be honest, I'm tired of oblivious/overprotective prince characters who may be righteous, but has a possessive side in these types of stories. We've seen them done to death. I don't hate the ship, but I wish there were more platonic subordinate relationships in stories like these.
Ernon and Kasia feels like a canon, but I might be putting my foot on my mouth with that statement.
I'd prefer Kasia with Ernon because they're both at the same pace, except one needs saving (Ernon) before he could be able to feel human and the other is on that journey to becoming a proper human being.
haha... It's like the Saintess and knight troupe except their genders reversed.