Amicus

The eldest son of the late emperor of Adastra and contestant for the now-vacant imperial throne. Visits Earth with the intent to take a human as his pet, but learns only after kidnapping Marco that humans are, in fact, highly intelligent, and that he has made unauthorized first contact with an alien species in grave violation of galactic law.
With only enough fuel in his technologically enigmatic Parental spaceship to make the return trip to his home planet, Amicus promises to return Marco to his home after he regains access to the Parents' technology by becoming the rightful emperor of Adastra.

Spoiler

Was publicly outed as a so-called "tail-raiser" (a slur for gay men on Adastra) at age 18 and continues to be followed by that reputation.