The identity of the founding god is unknown. In addition to the powers granted by the Monolith, Myridians have been genetically modified to be stronger than other humans; they are easily identifiable for the much wider variety of hair colors (including pink, blue and green).
Myridia experienced rapid growth: it went from iron age to industrial revolution in less then a century and had a planetary government a thousand years ago (Beyond The Impossible #25), until Demeter single-handedly conquered the planet and turned it into an absolute theocracy.
Under her dictatorship, technological and societal progress were stopped by the Oracles, Demeter's agents granted telekinesis by their goddess. Dissidents, worshipers of other gods and those incapable or unwilling to conceive children were brutally murdered.
After Noriko Null and the Vanguard arrived on Myridia, they started a rebellion leading to the overthrow of the regime. (Beyond The Impossible #28). Demeter reached Myridia in person, fighting the Vanguard and eventually being killed by Noriko Null. (Beyond The Impossible #28)
With the fall of Demeter, Myridia was a target for many hostile gods and was the subject of a heated dispute, being then assigned to Hermes (Beyond The Impossible #57). It later became a founding member of the Mortal Republic.
The planet was quickly rebuilt to its former glory. With many citizens worshiping Noriko Null as a goddess, the Church of Null was founded and came to be a very influential institution. During this period, Myridia was under assault by the Guild (from Beyond The Impossible 113 to from Beyond The Impossible 123),
First appereance: Beyond The Impossible #22
Capital City: Null City (previously called Deka)
Other known cities: New Rhetra
Population: 150 million (excluding duplicates)
Form of government: Presidential Republic. Absolute theocracy under the Demeter regime
Parent star: Castor in the Gemini constellation
Known facts: Myridia has a slightly higher surface gravity than Earth's, just enough to be noticeable
Trivia: Myridia is the first alien planet visited in the series, the only one identified with a real-life star, and the only one with multiple storylines to explore it. It is not the closest one, however: Eleusis is 20 light-years closer.