I think that Harry himself fits better the symbology. Harry starts as "potentially dangerous", he's the dark matter, and the during his journey he chooses to be better than Tom Riddle and starts a process of purification.

At the end of book 7 he dies, leaving his past self behind, and then he's resurrected as warrior and hero, but mostly as man. He chooses to fight for the things and people he loves the most and that's passion, but purified and made immortal.