The One-Eris Theory is a sociological concept in the fediverse, which is a decentralized network of interconnected social media platforms. According to this theory, all users who identify as "Eris," regardless of their location in the fediverse, are actually one single person with an indefinite number of alt accounts. This concept is similar to the One-Electron Theory in chemistry, which suggests that all electrons are the same and cannot be distinguished from one another. The One-Eris Theory has gained traction among some members of the fediverse community as a way to understand the complex and interconnected nature of the various platforms, and to explore the implications of identity and authenticity in online interactions. While not universally accepted, the One-Eris Theory continues to generate discussion and debate within the fediverse community.