By Taken from http://hosting-24300.tributes.com/show/Eris-Martin-Loomis-93929974, where it is/was stated: "photo. Museum (I.Gesk) © Berlin Antikensammlung", Public Domain, Link

Eris, the goddess of strife, appears only once in Protopia, yet her presence is felt throughout. She is not a villain, nor a mistake — she is a condition. Where she exists, cohesion shatters. Dialogue becomes noise. Cooperation gives way to rivalry. In the mythic universe of Protopia, Eris is the counterweight to Harmonia, her existential opposite. The two cannot occupy the same space or moment — not out of hatred, but because their natures cancel each other. Harmonia binds; Eris unravels.
Eris plays a singular role: she is the embodiment of fragmentation. While Harmonia reflects, connects, and restores, Eris injects division. She is invoked — never welcomed — in moments of breakdown, ego, or chaos. Though she appears only once, her legacy is that of a constant external pressure: the force civilization must resist to maintain coherence. She does not argue. She does not explain. She destabilizes.
Her presence reminds the reader that harmony is never default — it is constructed, protected, and always under threat. Eris is what must be absent for the world to improve.