[Zywack]

For archers, Shinuyama is obviously a great choice (4 types of national archers, all recruitable in every province, and easy access to flaming arrows)... However, the "no troops have shields" does put a damper on the whole thing, and they have no natural access to Astral and Air at all (although you do have national air summons that have points in air though if you have a pretender with it).

I wonder if Patala might be a good idea? They got mind-blowingly good capital mages (especially for late age), archers with longbows and decently durable troops. No fire, air or death access, though... And the best non-capital mages you have are 2 Astral 1 Nature. Could be a good pick to learn and practice using communions though (I'm currently doing that in a single player game).