[ they might not be those spartans of the ancient world, but these future ones were named after them for a very specific reason. if eric can put together the reference, he might be able to understand kelly better than most anyone else. and why the covenant soldiers think "spartan" is the human word for "demon."
right now, though, he doesn't seem to understand that being a spartan means she's been trained to fight for her entire life, so she pauses to figure out how to explain that without giving away classified information. ]
Fighting is what Spartans do best. [ they're fighting a losing war back in her universe, after all. ] What are you? I've never seen a human [ a human who isn't a spartan anyway ] fight like you.
[ she knows plenty of marines and odst fighters who would be able to put up a good fight if they had plenty of ammo and a good deal of distance between themselves and these things, but since they have neither here she's forced to conclude that he's not human. and because of her experience with an organization made up of alien races convinced that the human species should be wiped out of the universe, that realization is making her extremely wary. she doesn't want to have to fight him, too, but if he hates humanity the way the covenant does, he'd rather go down fighting her than team up with her to ensure they both survive against this other, more powerful and mutual enemy. better to die and take down the human demon than let it live. ]