Around 1619, Garrath Sharpsword aka Argrath Whitebull set up hidden shrine to Orlanth Victorious in the Big Rubble. From this shrine, Argrath and his friends and students regularly explore the Hero Plane seeking Orlanth’s magic and boons. It was from here that on Orlanth’s High Holy Day in 1620 Argrath began his quest for the Drinking Giant’s Cauldron, which some speculate resulted in the first Giant’s Cradle coming down the Zola Fel in some seven centuries.
One of the mysteries that often troubled scholars and commentators on the early years of Argrath was that the Lunars and other adventurers never found this shrine, and some truly bizarre explanations have been given. The truth is much simpler – it had no fixed point. Instead, Argrath used the topography of the Big Rubble as a microcosm and each time sanctified the shrine anew in a magical appropriate location! He and his companions brought regalia and statues, sanctified the magic circle, summoned spirits and gods, and from there entered the Hero Plane.

For as we all know, Garrath Sharpsword was a famous instructor who lives in Oldtown. He is known to worship Orlanth Adventurous, and has spent time among both the nomads of Prax and the wolf pirates of the Rozgali Ocean.
F-53 Training. Garrath Sharpsword: both shield and sword.
This adventurer teacher often disappears with friends and students on expeditions into the Rubble. He takes only students who can work a full day with him, cramming the lessons together. A former Sartarite, he fled after the Lunars invaded that land. He teaches broadsword, ride, medium shield, one-handed spear, dagger, and thrown dagger. Garrath Sharpsword is a regular at Gimpy’s.
One of the difficulties Gim Gim the Grim had is that the Air Temple had too many friends to shut down (at least as prior to the Cradle fiasco) and Sor-eel found unofficially tolerating the Orlanth cult a useful way to get adventurers to explore the Rubble and its treasures instead of causing trouble for the Empire. And Gim Gim had his own agenda and network that was focused on things other than the Orlanth cult.
And so Gim Gim never did unravel the mystery of the hidden Orlanth shrine (admittedly it was not a high priority) nor realize that the instructor Garrath Sharpsword would become an existential threat to the Empire. At least not until it was too late.

But Gim Gim did manage to exercise surprising amount of control over the city of New Pavis with his Moon Masks, make contacts and connections with the Black Fang cult and some even more unseemly groups, and make himself very wealthy in the process. Not bad for a guy wearing a Red Moon Mask!
Which I figure was actually pretty intimidating!
Note that not every title is a subcult! Orlanth Victorious is the title of Orlanth as he heads off on the Lightbringers Quest (eg Hill of Orlanth Victorious in Sartar). It can be thought of as the “fully integrated Orlanth” – Adventurous+Thunderous+Rex. Invoking him has dangers, as you are opening the door on the Lightbringers Quest and summoning enemies and opponents (as well as allies and friends).
Given how small Argrath’s cult was in 1619-1621 (maybe no more than 75-100 people and spirits), we can assume that every time Orlanth Victorious was invoked, they had to overcome adversaries at great risk. And we can imagine what sort of things might show up in the Rubble – dark trolls, broos, God Learner spirits, you name it.
So if you imagine Garrath Sharpsword circa 1621 – he’s very skilled at sword, shield, riding, spear, dagger, and thrown dagger. He is lean and wiry man, very charismatic, with the sort of quiet self-confidence only a person who has lost everything and then rebuilt himself up is able to have. He easily passed the test of the Weaponsmasters Guild, which gave him the right to have an independent school, wear his arms openly, and a degree of freedom despite being openly a Wind Lord of Orlanth Adventurous. He is fluent in Praxian (as well as Sartarite) and has many Praxian friends – mainly Bison Riders and High Llamas, but some Sable Riders and Impala Riders as well. He’s more comfortable in the company of his students, Praxian shamans, or adventurers than he is with the Garhound clan leaders or city leaders, and stays out of city and temple politics.
Gim Gim the Grim is thought to consider him one of the Orlanth Allies, and the Moon Masks keep an eye on him, but given that he heads a recognized weapons school, they avoid harassing him or his students too much. Gim Gim keeps Krogar Wolfhelm and Govoran the Magnificent (who of course has his own mercenary band) under far more scrutiny.