Church, mercenaries and war

 Once again I subject you to more world building because I've got a sudden interest in developing the setting I've been going on about in a new direction, so let's talk war!
(Also, this proved to be great background music for writing.)

The only problem here is that to talk war, we need someone or something to be in war with. Or even two nations or other such forces that would clash in the first place.

Well, we have the church of Varchic and the cult of the Deep but that conflict I would like to keep as something internal to the nation with the cult laying low while the church tries to root out the heretics with varying methods.
So that's out of the window.

Another option would be to introduce some pagan religion(s) the church actively fights with but I again feel like I'll rather leave those to instead be only remnants of such faiths that mostly just stick around the local countrysides or other older places as traditions that the church has not been able to quite root out.The remains of a world much older and shamanistic than the era people are currently living in if you may.

But, I've lately been playing Urtuk: The Desolation and am really liking the wasteland aesthetic of it which is giving me urges to put some sort of area completely ruined and wasted by warfare into this world.
Maybe somewhere east of the Ecclesiarchy of the Pit there is a wasteland left behind by a holy war. Smaller towns and villages might not even know of this endless battlefield with how self-contained the church-capital is from rest of the settlements under it's influence, but every year a retinue of clerics and knights of the church march eastwards with only a handful of them returning back.
This is also another reason why news of the holy war are not actively spreading across the nation. The mustering of troops is handled purely from those who have travelled to the church-capital to serve under the church of Varchic and only few of those men and women ever make it back, leaving not too many mouths to spread rumours.
Communications from the war efforts are mostly handled by pidgeons, although if there are yet any higher ranking priests left leading the armies in the east, it is likely that they also have some more secure ways of communications between them and the church-capital.

How I imagine the war efforts looking like, just with less rats and more humans

This seems like a good enough way to include war within the setting while still leaving room for it to develop. Maybe in time the holy war will become more widely known within the domain of the church of Varchic and even the smaller towns will have to start providing resources or troops, or maybe whatever they are fighting will manage to push back the holy army of Varchirch.

Simply pushing towards exploring that area would make for yet another different backdrop for an adventure or two when I figure out what the church is fighting over there as I'm not sure if I want to make it just simply some eldritch mosnters or another nation of sufficiently different culture. Probably the latter as most of the time if one would be thinking of using humanoid monsters it's more dramatic to simply using humans with different reasons or morals behind them.

As for my want of mercenaries, it will likely be a mixture of small inquisitive missionary groups of the church weeding out heretics from the countryside as well as independent parties roving between towns in search of work and people in need their services for protection.

Next up I'll likely have to start actually giving all these factions and their sub-factions some named characters to give them just that extra bit of structure and something for me to draw from and solidify the ideas of the factions around, but that'll be another ramble for another time.