I like it that they may both be powerful spiritual beings, and that they are enemies, but neither of them is evil. I suppose Keats may turn out to be evil, and what he was doing was consuming the woman's energy or something rather than easing her passing. I hope not. Also, I hope nothing like this is ever made quite explicit. I'm sure it won't be.
Speaking of things never made explicit, did you see the graffiti Alex was looking at on the underpass:
I'm such an idiot fangirl because that gave me a massive tingly thrill.
And just as I was about to hit 'post' I see rozk has just posted a similar chain of thought about Hunt and Keats, though she argues that Keats is Lucifer, and you could make a case for that. And Lucifer is an ambiguous figure.