first prince (or a secret prince), because of his words specifically. First and last festival? Sounds like someone who was either kept away all this time or locked away, but now is about to take up the mantle of his title and as a Royal could never walk the streets of a festival. And the idea of him wanting to enjoy his remaining time, as a commoner, fits that as well. Once he debuts as his title he can't go back to that peaceful life anymore. Although does annoy me a bit as this means that in both the past life, and this new one, A and J will fight over a boy.