Eris is more than a Greek god and Ares' sister. She's also the biggest dwarf planet in the Solar System, considerably larger than Pluto. It has its own moon, Dysnomia, or "lawlessness," named after Eris' daughter.
The astronomer who named her, Mike Brown, who has explained that he named the dwarf planet after his favorite goddess. Brown's book, How I Killed Pluto and Why It Had It Coming, goes into considerable detail about the legend of Eris and the golden apple and the origin of the Trojan war. Brown's book title is oddly reminiscent of the subtitle of Principia Discordia, "How I Found Goddess and What I Did to Her When I Found Her."