Order of Heliud
The Order of Heliud is a religious organization that expanded across numerous planes. It strives to bring “harmony, protection, and law to the Multiverse".
One particular sect of the order sought to bring law to the plane of Regatha through hieromancy, the magic of holy justice. They sent people they deemed criminal into the Purifying Fire, which probed the soul for sin and was able to destroy a mortal being or drain all power from a planeswalker, including the ability to planeswalk.
The purifying fire drew the attention of Gideon Jura, who agreed to serve as an agent of the Order for a chance to study the flame. His strong morals and sense of duty meant that he soon found himself in agreement with the Order's purpose, but he never committed himself to them fully. He was sent to apprehend the pyromancer Chandra Nalaar for the threat she posed to the Order's goals.
The sect of the Order on Regatha was led by Walbert, who had ulterior motives for wanting Chandra out of the way. Gideon eventually returned with Chandra. With Gideon's help, however, Chandra survived Walbert's persecution and gave Gideon reason to question the Order's true motives.
Planeswalkers who are aware of both the Order of Heliud on Regatha and the sun god Heliod on Theros, such as Gideon, speculate that there may be some connection between the two — but no concrete association has so far presented itself. Gideon also stated the sect stretched across various planes in the multiverse, with agents traveling between them, meaning there were several planeswalkers working for it.