<i>Cardassian Physiology:</i> Garak is not human, and he's staying not human when he comes through the 'Porter. As a Cardassian, he is grey-skinned with distinctive ridges and reptilian. The former means that he's quite obviously alien. The latter means that he's cold-blooded, making him much more comfortable in the heat than in the cold.

<i>Presence Manipulation:</i> In the training of his youth, Garak learned to manipulate his own presence and sense that of others in ways that bordered on the psychic. There, that was a matter of being extraordinarily observant, self-controlled, and psychologically malleable. Here, it's now a matter of actually being mildly psychic. While he can't read minds and feelings or communicate telepathically, he <i>can</i> sense hidden beings, detect when someone is exerting psychic influence, and accurately gauge the emotional state of a group. He can also do something he calls "withdrawing his presence." This means that he makes himself seem so insignificant and inconspicuous that he almost blends in with his surroundings. This is not true invisibility, however; someone with very keen observational skills (like he has) or intense focus can still notice him. But most people won't.