(I originally posted this in response to a thread on the Hellenistai forum. You can go there to comment or, if you’d prefer, comment here.)
Eris is a Goddess who is kind of like a Feminine counterpart to Ares and an “opposing forse” to Eros (in some Hellenic traditions, at least) in much the same way that Ares is an opposite to Aphrodite. Intriguingly, some mythos also pair Her as a “consort” or daughter of Ares similarly to how Eros is paired as a Son to Aphrodite — in that sense, like Eros, She has a “trickster” quality.
I don’t really worship Her in the way that some of my Discordian friends do, but like the nice ladies who already answered your question, I have a deep respect for Her. She’s nothing at all like the Christian view of Lucifer / Satan — she’s not actively malevolent, nor is she spiteful. She’s the goddess of Strife and Discord in the way that Eros is a God of Joy and Harmony — and just because Strife and Discord are unpleasant feelings doesn’t mean that they’re necessarily brought on by malevolent forces — likewise, joy and harmony can be brought about through active destruction (“schadenfreude”, as the Germans would say). Eris’ personality is more like that of the comic book standard of the “pixie girl” who causes trouble then feigns wide-eyed innocence that everybody who knows her knows is a crock — she doesn’t do it so much out of malevolence, but because it gives Her short-term amusement before moving on to the next victim of her pranks. In this sense, Eros and Eris and interconnected in a way similar to but far more intense than Aphrodite and Ares — remove Eros or Eris from each-other completely, and the other becomes completely meaningless, whereas removing Aphrodite from Ares or vice-versa makes the God of War seem psychotic and the Goddess of Love seem flaky, but otherwise viable on their own.
And in this way, I suppose, one could say that Eros and Eris are like the “trickster elder Gods” to Aphrodite and Ares’ more “mature” or “streamlined” younger Olympians.