I'm a well read grad student who's bluntly honest about all things, although I try to be most honest about myself.
A plothole and a spoiler.
Pretty major plothole: it was explained earlier - in the comics and in linear time - that Killian wanted Aspen in the first place because she was supposedly part of The Black. Which meant she was akin to a god to The Blue - and she's half Blue, raised by humans. (And there's a prophecy that she will bring balance to all three worlds.)
What this means, though, is that Killian knows this. The fact that he tries to explain what the Black to her may make sense; he's been out of her life long enough that he might not realize she knows this. (In order to keep her under his thumb, he never revealed she was part of The Black.) However, this reads like he didn't realize, because she makes this claim and this feels like a revelatory moment. Is shouldn't be, though.