For the backstory, I think the mane thing (see what I did there?) to keep in mind is that if you're gonna RP as that character, you need to either create him with personality traits that you also have OR at least be experienced in theatre. If you're unable to put yourself in his shoes and understand his motivations, you won't be able to really get into character and make him feel real. So, I'd start with his basic personality traits and build the backstory around that.