I've got a few, but if I had to boil it down to a single one, it would be legacy. Aden bears the weight of the hopes and desires of several people from his backstory, including perceived ones that may be non-existent (as in the case of his absent birth parents). Nearly everything he does is in some way in pursuit of that. A secondary theme locked in with legacy would be the sins of the parents--Aden wouldn't exist save for some very poor life choices on the part of his birth parents, wouldn't be in the situation he's in but for yet more questionable choices, and one day some of their more egregious mistakes may come knocking.
Some day his thematic focus may shift, as he's a growing character, but that will likely always be a core aspect.
Some day his thematic focus may shift, as he's a growing character, but that will likely always be a core aspect.