Eris represents some sort of tipping point in the game. One that I suspect has to do with the fact that I believe we are not involved in a struggle between Good and Evil, but between other, more fundamental forces. Like Creation v Destruction....or Order v Chaos Which means that we might realize that (ultimately) it may be in our intersts for NEITHER **side*** to win. Because we may find out that we are simply pawns in a conflict where neither side really has what is in our best interests at-heart. What I think will happen is that Eris represents an IN-BETWEEN point. A nexus between the Light and the DARK. She is clearly a Guardian who was forged in Light....but was able to survive for many years by making use of the Dark. She refers/referred to Mara Sov as "My Queen"...so I wonder if she was originally "Awoken". Which means she was touched by the Dark...and has some powers that might find their source in the Dark. Lastly, although she is a Hunter, she clealry also has the powers and sensibilities of a Warlock. So I think she will play a vital role in us understanding exactly what The Darkness ulitmately is.....and will play a vital role in what is the ultimate resolution of this conflict in the Destiny Universe.