So the prince is related to the blond mage (cousin) from one of his parents. Let's say Parent A. Parent B is related to the Diarmuid (The tower master mage dude), so the blond mage is also cousins with MC. Jaina, the MC, is not related to the prince. Hope that helped!
I think the blond haired mage (Jaina's cousin) , his mother was as I remembered was Diarmud sister and his father is of royalty or vice versa. So the Prince and Jaina are unrelated to each other.
I'm kinda confused about what age she's supposed to be like in some panels she looked like she was in her teen and then others she's being carried like a child
siblings or dating final boss
I mean at this point we can tell they really aren't siblings