Is your character a magic user/otherwise magical in some way?: Blood Elf mage! Magic addict and such. I assume you know the basics.
If yes, can Artemis "sense" this?: Hell yes he probably reeks of magic.
If yes, is there any specific impression that he would get from them?: He's mostly skilled with the arcane, which is basically pure magic magic. He also is very reluctantly skilled with fire magic.
Anything else?: butts.