Due to the disparate nature of most of the cultures of Southern Heimr as well as a lack of a central government, the Utgardian Military as such does not really exist. Most of the area of Southern Heimr is inherently lawless, with random tribes of Ogres roaming around attacking almost anyone on sight and Orc houses fighting for scraps of land, among other things. Yet at the same time, it is hard to actually conquer the lands, otherwise the Asgardians would already have done so. This in part is due to the same lawless nature. Many of the groups living in Southern Heimr are nomadic and hard to track. Also, due to the same nature, most of these groups are heavily armed and capable fighters, which makes them a threat to even the largest army, especially since they can suddenly show up and attack valuable supply trains while the main body of the army has already moved on.
Utgardian Armies
While this lack of centralisation makes it hard for an army to invade the lands of Southern Heimr, it also means that there is almost no chance of a successful attack from those same lands. The scattered groups will at times and with the right persuasion form up into a large force, but this force often can be considered to be more of a mob rather than a real army. There is no guarantee any of the groups within the larger force will remain with the force while they travel - and even if they do, there is quite some chance they will simply attack a different target than the other groups in the force.
Another problem that arises with these armies is that, while they now operate with mostly the same goals, most of the rivalries between groups are not put down and can flare up again. This infighting may even happen in the middle of a battle, facing a common enemy. Battles can and have been lost due to internal infighting in the army.
Commanding an army like this would make even one of Ratish's daemons cry. Thus, most of the times these armies end up without any central command or structure, meaning they also lack any central direction. Instead they just rampage around, across Midgardian and Asgardian borders, until the army falls apart. Central commanders have been known to arise within the armies, however. These are most of the times Orcs, being the only race in Southern Heimr with enough insight into strategy to want a centralised command and at the same time being able to beat an Ogre into submission. These commanders need to command purely by strength and wit, trying to either beat or coerce the rest of the army to do what the commander wants.
Utgard Alliance Military
Main Article: Utgard Alliance Military
One branch of the Utgard Alliance is an exception to these mobs. The Utgard Alliance Military is a comparatively small force tasked primarily with protecting the borders between Zarashal and Lhengard and Caldera Wasteland and The Uplands . It is mostly a volunteer army, meaning it primarily consists of outcasts, criminals and other lowlifes. It is somewhat more organised, but still very decentralised. Communication lines in Southern Heimr are long and slow, a message from Guardian's Point easily takes several weeks to reach Evermine . This means that each Utgard Alliance outpost ends up on its own. The commanders of these outposts are even explicitly given the freedom to do as they please due to this, as long as they protect the border. This is the primary reason there are still people joining the ranks of the Utgard Alliance military, since you will have a roof above your head, you will be fed and, if you work hard, you might just end up being in command at one point or another.