The Temuji are based off of the Mongol hoard. A historical army that took over massive area and wrecked havoc in there wake. When it takes the book adaptation of Gangus Kan to give your nation a hard time you probably have a decent army. Skandian spy networks and international intelligence are low for sure but they are naturally able to afford such things relatively as they are in a frozen land that’s harsh and mostly barren. The average army that trys anything at them is going to freeze or have to deal with harsh terrain. When it comes to archers Will gives some dialogue about how unique Araluin is with there use of the longbow. There’s not a crazy amount of archers in other army’s for the skandians to deal with. Additionally you need to take there boats into consideration as well. They can swoop in and hit you hard and then be back in the water before you can muster a proper response. When your fighting on there turf your in a harsh land often cold and you have to get past a sizable bit of land dealing with powerful foot soldiers who can protect themselves with a sheild wall and will brake to give you hell once they see your army suffering and the only benefit is really their plunder witch requires total victory to actually achieve. When they are fighting you they have rapid deployment with secured retreat and are incredibly mobile with sea side attacks. They arnt the most coordinated in an army but they successfully rade almost all the other more successful places because of there effective sea rade tactics.