Again, the Argentiums in general.

They're one of the few groups in Unova that's well-versed in Aura and Martial Arts (both of them are intertwined since Aura is also referred to as "Ki" in the Murim). Typically, Elio and the rest spent their entire lives honing their respective Auras and martial prowess - both of which have been proven to have beneficial effects on the body when honed properly, so they have a damn good handle on it. However, it doesn't mean they're invincible, as Aura mastery has grades and people of higher levels naturally exist.

If you wanna think of Aura in another way, think cultivation from Wuxia.

This extends to their Pokemon as well, since Pokemon are more potent Aura users than humans - which would partially explain why an Argentium's party members are unusually strong, even by veteran standards.

Not quite sure how to go about for this one, in part because I'm not a hundred percent on the question.

Do we mean the character's presence?
If so then Dawn possesses a very strong presence; spoken or not, she exudes an air of confidence and compassion. She has a rather difficult time withholding such, however. Dusk, on the other hand, can potentially exude a rather dense, threatening air (especially postgame); a wash of unspoken charisma amplified by an unblinking stare that demands would-be challenges to step aside. He otherwise is more capable of slipping into a crowd and remain unnoticed.

Are we discussing Aura in the fighting-type sense?
If so, then there's Foley. His senses are supreme and innate talents lend to an astonishingly accurate judge of character. In spite of his distressing wealth of potential, he simply dismisses them as 'being able to read people', and even takes a degree of offense if others suggest indulging in what he considers nothing more than superstition.