This is just my personal theory. If you don't like it, DON'T COMMENT ON IT.
Thank you.
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Now that we have been introduced to Abel (Adam's younger son) it seems to me that we may also be introduced to Cain (Adam's older son). while I don't want to make any big assumtions, I would like to think that maybe the sons of adam will play important roles in season two.
First of all, their personalities and in cain's case, apperance =
Cain:
since his brother is shown to be quiet chubby (but very cute) I think that cain would look more towards the emo pretty boy look with dragon elements thrown in. due to him being the first murderer and thus the first sinner, cain is feared by everyone in both heaven and hell alike, to the point where even saying his name will invoke fear (ala voldemort)
As for his personality, I like to think of Cain as stoic, calm, cold, calculating, patient, and much more mature than his father. He's very no-nonsense and will never hesitate to get the job done. If he had to kill Charlie in " The Show Must Go On," he'd waste no time in bragging or mocking her and just DO IT.
While he is mostly unfriendly, cain isn't without his redeeming qualities. he is known to be loyal, honourable, fair minded, empathetic and fiercely protective of those he can trust. he's also known to be a good boss to his army of snakes and lizard-men, praising them for doing a job well and not pushing them too far if they cannot continue.
Like his father, Cain also likes music, being able to sing and play the organ, flute and piano. he is also able to conjure and control thorny vines of darkness, control shadows, command an army of snakes and lizard-men, breath and control dragon-fire, swordfight and can transform into a dragon at will. he also has a sword that can set itself aflame.
Abel;
While his parents quite spoiled him, cain is as sweet as can be, if a little bit pushy (think charlotte from princess and the frog but a guy). Abel is also very modest and friendly, but can be a bit insensitive at times. he runs the heavenly marching band and is good friends with emily and molly (angel dust's sister)
Unlike his dad, Abel never liked the idea of exterminating sinners and when he's offered a job as the new head exosist, he instead abolishes the exocists, leading lute on a downward mental spiral. he also misses cain dearly and even though he's constantly been told that cain killed him, Abel doesn't remember seeing cain anywhere near him during his murder.
He has the ability to ring the bells of harmony (special angel bells) is good at baking and has the abilities of flight, organisation, party planning, conjuring weapons of light and casting protection spells.