Responses
In the 9th chapter the one being held in the dude's arms is actually the real Theodore and the one supporting Arlo's side is the real Prince(Radol). And to the panel where we see a hand and Arlo (ch9), was the prince's hand letting go of Arlo and moving away from sight, that's when Arlo panicked.
THANK YOU FOR THE EXPLANATION （/TДT)/ you're a hero
I think, the prince (Radol) and the substitute (Theodore) switched places and names before the real prince drowned (ch 7), the prince was drifted at the place where the substitute once worked at, thus why he now works at the brothel. And the substitute is acting in his stead. Acting like the villain to make the palace traitors (see ch7) THINK they manipulated the substitute into killing the real prince.
And also on ch 8, the real Theodore worked at the brothel in his childhood days, until he was hired to act as the prince's substitute. And he didn't want to go back there(the brothel) so he felt guilty staying in the palace ch8.