Tommy differentiates himself from the trashier and most dangerous slums of my head because he is not narcissistic. Quite far from it, in fact. It's not something many can say (Sarhen does not count). He doesn't have a Klaus kind of ego, doesn't think he is particularly perfect in any regard, isn't vain, and isn't even confident per se. He does believe himself to be entitled to things/people he shouldn't feel entitled to but it's not particularly because he is any better or in higher grounds than they are, it's just because he lacks, above all, self control over his most harmful impulses – impulses in general, honestly. He is made up of curiosity and whim and if he wants something, if the hunger strikes, it's really hard for him to stop himself. It comes with being half-demon, one can suppose, that with the little temptation issue...
But he isn't narcissistic. He isn't vain, and he isn't even confident. His skills as a box man and as a pilot are worthy of envy, but his people skills are lack luster and his relationship record leaves a lot to be desired (looks can only be charming for so long!). He can be as intelligent as can be, but having Nicholas Acardi for a brother will intensify the light through which you view your imperfections, especially at dealing with people. People-dealing =/= Tommy. He isn't good with words, he isn't brave, and he isn't a lot of the things he especially looks up to in his older brother. His sense of worth takes a hit thanks to this: it's heavily – so very heavily – dependent upon what Nico thinks of him, it's when Tommy loses him – when Nico goes to prison – that his self control begins to falter and suffer (because he wasn't always this trigger happy little shit with a penchant for gruesome murder; he was, in fact, well put and organized and clinical, if not slightly inept) until it becomes moot. Why does this happen? Because he loses his frame of reference. He loses the one person he can be sure loves him. Self worth drops, sense of boundaries and limitations drops, predisposition to violence rises, fixation rises, Tommy Acardi as he is nowadays is born. Even after he gets Nicholas back, the damage has been done; Tommy has become unpredictable and blood-thirsty and unprofessional. But really not narcissistic, not at all. Far from it.