Region: The Western Isles
Mainland Athara Magarat is an inhospitable place where everything is trying to kill you (part of reason why I have a 60 million plus diaspora whereas I am the third least populated Isles country). Add to that the culture which granted promotions based on how much "prestige" you gathered on the battlefield. Every house would have at least one children sent to the army (even girls if the family had no boys; no exceptions). When they could not get into local armies, they became mercenaries. Some of these war-loving idiots even fought for enemies against their own nation.
This "prestige" thing was necessary to become a hang or virtually any other higher rank official (though only candidates from House of Mgar could become Mahangs, anyone could become a hang or hangma). There were other ways to gain prestige (like marrying a former High Kumari for example) but the battlefield was the best option.
And add to that, the imperial decree after so-called "Magarati Peace" which forbade hangates from waging territorial wars against each other...How does your hang (from Mgar dynasty) get more prestige than his cousins if no territorial wars? Either you go on colonization spree like Chatha, have powerful foreign allies like Arun Valley did or find any lame excuse to declare not-territorial war and hope that your side wins.