[quote=GreivousKhan]
Adjutor Insula btw has around 350,000 people yet can some how support 20,000 in their military? o.o
[/quote]

Well as the overall rule I take to consideration is that a medieval lord can raise an army of 10% of their population (~10% of which would be devoted to offensive operations). Ten percent of 350,000 would be 35,000. So they're not at that limit before they experience long-term economic deficits.

And if they're a sort of holy order with land, then many of those recruits could also be foreign proselytes who came to them for whatever reason: adhering to their faith, needing to start again, whichever. So they could not actually be "natives". Most of these could also pull double-duty, being an island have a trade fleet would be vital to their economy, so some soldiers could pull double-duty as an armed merchant marine: active in the order's mission but keeping the cogs of economy moving and pushing out their exports.