According to this -- https://www.scribd.com/doc/161099025/5/GEOGRAPHY-OF-MULHORAND
-- Set is likely to be found in Sampranasz. The material mentions that there's a lot of ruins, but that is likely due to the number of times it has been destroyed (once during orcgate wars, twice after by natural disaster) so this may not be the case in present day RP. Even though the governing seems to be done by someone appointed by the priests of the chief deity, but even then they seem to be in Set's pocket. Basically...
The town is a fishing port. Its coastline has some marshland where papyrus can be found in abundance. The town has a population of 3,000; those who do not serve Set disappear very quickly.
Sampranasz is also the closest city to Skuld, so you wouldn't be too far off in trying to stick your nose in its affairs at all, Pale. Do note that just about every Mulhorandi deity (including even Sebek to a degree) dislikes Set, which is why the clergy tend to have to rely on sneakery and subterfuge to not get found and routed out. Hell, even Sebek's major holy city location was done in because Sebek is not the most tolerated... and it was Paladins of Osiris (with Horus-Re's tactic approval) that did it. It is not unheard of for some holy orders to strike out against the orders of those less tasteful... in fact, that seems to be a rather recurring theme throughout history.
Also, it is worth noting that those maps are *current* maps and not entirely accurate renditions of the current powers that be. Where exactly Set was most prominently seen before is not touched upon and could very well be most prominently found in other ruins.
If you look at the Mulhorand Complete Map...
Basically *everything* belongs to either Unther or Mulhorand. About 180 years before the event of the orc gate -- just to give you an idea of how expansive these empires are -- Unther was battling against the elves of Yuirwood (look at that patch of green waaaaaaaay up in the north) and the dwarves of The Great Rift (see that brown splotch waaaaaaaay in the south?). Since Thay eventually seceded from Mulhorand, I think the Lapentmar River (or whatever it is, I can't read the name too well) is the natural northern boundary between the two empires, while the River of Swords (attached to the Lake of Salt) is detailed clearly as the southern boundary. The northern coastal cities (such as Bezantur) didn't naturally show up in the northern part until later on, but it can be every bit assumed that both empires have military power and the potential to try to found a city (meaning it might be possible to found them in that area assuming Zaer's fine with it?).
Thay doesn't yet exist, Chessenta doesn't yet exist... *lots* of space to hold, and even more space to be conquered.
Also, I am just speaking from what I've managed to glean from a few things; the details are likely better retrieved from Zaer, and his word obviously overrides. It is also further assuming that things remain relatively linear to base material; it's likely that things could greatly change if the concept is run in a different direction.
My holy order will indeed set up shop in Mishtan near the Land of the Dead to construct the tombs and of deceased and whatnot. That being said, there will still be at least a small measure of open presence of Osiris throughout the entirety of Mulhorand, ideally (or at least the most populated), as some artisans go out to do charitable work and clergy aid in burial proceedings. The militant power will likely be constrained at Mishtan until such time that they are given a directive, whether it be for defensive purposes (against the Orcs) or internal affairs (Cults of Set); even if they may hold bias against certain groups, they'll largely refrain from taking overt action until either there is direct and measurable harm (a Paladin of Osiris wouldn't just walk past a criminal act) or they are mobilized for specific purposes.
Dedicated to the sanctity and protection of those that have passed on, the Order of Sheltered Repose is dedicated to the teachings and values held by Osiris. The God-King -- Abel Anszir -- heads the church and is a well-known for his more defensive, protective inclinations and prominent connection with the deity Himself. Most of the people involved in the Order of Sheltered Repose are pacifistic artisans or clergy members that seek to bring peace to those deceased and left behind while others remain behind to assist in the Land of the Dead, the expansive tombs of pharaohs past and present. Among those people, those with talent are hand-selected for more militant matters when the order's hand is forced, though most are specialized in tracking than open combat; even if an atrocity is committed far away or out of sight, the Order of Sheltered Repose will chase with a guided tenacity to mete out suitable punishment to those involved.
Artisan Culture: With an emphasis on construction and a lot of time and freedom to explore their craft, those of the order are very talented, specifically in the realm of Architecture and ornate design.
Exploited: More a symbol of their charitable nature than of the exploitation of others, per se, the order makes less money than they otherwise would despite their advanced craft.
Fortifications: With such advanced knowledge of building tombs and structures that will last through generations, fortifications come naturally.
Magic is Rare: Though magic is treated with caution and scrutiny, Abel sees it as an unfortunately necessary evil for times of trouble and moments of duress. Magic items are a rare commodity to come by, and the followers that do come across them in their travels are heavily incentivized to donate it to the figures with greater power who can best put it to use.
God's Favor (Repose): Osiris Himself favors the Order of Sheltered Repose, and this is made clearly manifest through the greater ease by which clergy make use of this domain.
I'll have my God King's stuff finalized in the near future, but to tease...
Nimbus of Light, Holy Radiance, and Touch of Golden Ice are all feats that I picked out for him. He literally sheds light, causes nearby undead to take damage, and naturally "poisons" evil creatures through contact.