[@Bishop] They are negative magic/energy, yes. Him(it?) absorbing the negative energy wouldn't void it, though it may make it weaker. Given that if darkness absorbed/fed on someone's anger, it wouldn't make the person less angry, y'see?

Also, witches aren't attuned to the dark side. Like my character's CS says as well, he's the last living witch so you may need to adjust that sentence in your IC.