Not sure we are on the same page here. Y'see, all I'm saying is that higgh priests in the Stickverse tend to be the heads of a church, and more specifically the church
of someone (i.e. some god) in particular, rather than the heads of a
national/regional, autocephalous organization, i.e. the church
of somewhere (is it inappropriate to bring up the way a real life church is organised as an analogy? It would make my job a lot easier).
For example, each Northern god has
one formal high priest(ess), which would imply that Northern gods have separate churches of their own, and each of them has exactly
one such formal church. The same seems to be the case with the Dark One, as well as the Western gods (at some point, Malack
makes mention of the high priestess of Ishtar, while
Wrecan says he works for the church of Marduk).
Since other high priests are
the formal heads of
the respective churches of their gods, and since the Twelve are worshipped as a unified pantheon, I took the liberty to assume that
the (singular, unitary) church of the Twelve is a thing, and therefore the high priest of the Twelve we see in Azure City is indeed
the formal high priest of the Southern pantheon, rather than the leader of some local organization(, due to which, in turn, I took the liberty to assume that the Church of the Twelve was headquartered in Azure City at the time of the siege).