Elionism is the official religion of the Republic of Calpheon. It takes its name from Elion, its God and object of worship. It seems its origins are based in the region of Calpheon, and it's said its foundation predates the foundation of the kingdom (of Calpheon).
It's faith and worship is regulated by a Calpheonian institution called the Elionian Church (or Church of Elion), which has always been a major power of the state. The Church is headed by a High Priest and its priests are sent to all the lands the state controls to proselytize. There has been an ongoing effort to convert the population of both Balenos and Serendia.
It is also said Lord Elion himself founded a city between heaven and earth to manage the affairs of the human realm and stationed overseers there, a trait shared between Elionism and other myths and minor religions. Its faith is so extended in Calpheon proper that the prior central church of Elionism, Falres Elionian Church, was considered the center of the capital, Calpheon City. The state also forces all people entering it to be purified by an Elionian priest and undergo some admission procedures. Any common folk who is permitted to enter its land is to be considered a citizen of Calpheon and a follower of Elion.
Followers of the faith believe they're sent to Elion after death.
Excerpt of the Holy Scripture:
Holy Scripture, Chapter one
"In the beginning, Elion created the plains, trees, and animals with the Black Stone. Finally, he created the civilized ones. Elion taught that heretics should be warned three times of their transgressions.
If they ultimately fail to change their ways, they should be left alone. The heretic will soon come to realize the way of Elion is the true way, and that Elion is the one and only savior. One of the distinguishing characteristics of a heretic is his or her denial of the scripture's infallibility."