As for the latter, the military too was not a new word even in Noseth.
Prior to the innovation of David, various human countries in Noseth did not have a real standing army with professional officers.
All the barbaric lesser-being demihuman fought in disorderly ways with only brave and individual ability as a tool. Since most of the time they were individually stronger physically, they could hold a fight and win against human in one on one but would lose in battles and wars. More than 500 years ago great war broken between demihuman confederation and emerging hegemony human country Ramela republic, the battle ended with human destroyed the demihuman confederation, thus many tribes retreated to southern continent using the natural barriers as a wall against human, as for those tribes that were deceived to stay and believe in human's promises or did not directly participated in war, mostly the demihuman of the time who did not escape from the human world would have found themselves in slave markets around the central plain.
If they were lucky to flee far enough to a good place like the less crowd area on the northern plateau and western desert, they would at least gain respect as a human equal in nomadic tribes. There were those that decided to fight around the forest land near the further east, most of them joined hand with some good nature human and create a coexist country. As times went on the matter of discrimination was less even in the ringleader of demihuman extermination like Ramale republic and the demihuman slaves at least get the treatment better than livestock.
In the case of David, Vatsa was a very open-minded country and all race would be treated as equal by the crown, David's father in law policy almost tripling Vatsa population with a loyal workforce who actually became an engine that helped with the growth and stability of Vatsa royalty power, the cons was that the process led to neighboring countries discontent. The discontent from neighboring countries rulers was over when they joined hand in hands to invade Vatsa. The war was bloody, they gained early advantage and success in killing the king of Vatsa younger brother, but their victory was denied by the hand of a young count who took command in the midst of the dire situation and turned the table.
There was other high races in Noseth, the elves, and the dwarves, which human need to respect as equal. They were greater than human in some ways, dwarves were better at blacksmiths and physical aspect, while elves had better force capacity and longer lifespan. The conflict between them did occur in some place but not big enough to become a problem, and instead of a war between them and human, it was likely a war between elves and dwarves would happen before, especially when the human and elves became very close.
As for human, most of the small tribes were the same as demihuman, they lived semi-nomadic life, while from the small kingdoms to the middle size kingdoms relied on volunteer militia organized by officer from the city mostly the young men in various dojo and sect, some wealthy enough country may employed knights order, the king may ask to use private forces gathered by the nobility class in exchange of ranks or spoils of war, and some would hire mercenaries from those capable of fighting outside their country.
While there was some exception like some city-state near the south of the lake that had all male citizen in the city as a trained fighter, or in some city around the northern part of the lake they had a professional troop consisted only specially selected male citizen.
Ramale republic, the former largest country on the continent, had a unique way of handling their force into four types of troops; the young blood, the eagerly for experienced, the veteran and the spear holder. Their military almost reached the concept of standardized but still not at the level of David's military force.
The good thing in Noseth military would be how normal citizen often count out from war duty. A number was indeed better than nothing but to lose a production force would be a loss for those of elite class and thus became a norm for every ruler to spare the common people unless the battle would be the total destruction of a country.
We could not conclude the Noseth military power fall lower than that of earth Medieval since there was magic, and 100 veteran martial artists could outrun a horse and when they stand in phalanxes bracing themselves with force even an elephant charge would be stopped by them. but it was sure that their management in the military structure was equally bad or lower.
However, the military force under David command was all standing army. It composed of full-time soldiers, career for those employed as soldiers, and would not be disbanded until retirement. Unlike temporary armies around Noseth which raised from the those capable of fighting, during an emergency in self-defense or easily gathered under the prospect of raiding looting and fame, just to disbanded during times of peace.
Was standing army strong?
It deepened on occasion, but almost all the time professional soldiers were a lot better than civilian holding weapons for the first time.
In the era of cold steel, a man trained for a decade living on the battlefield would be able to slaughter an untrained civilian who never killed a person before very easily. Projectile weapons could help the peasants to fight against fully equipped warriors but they would be nothing when it turned into melee combat.
Imagine yourself were stood face to face with a serial killer who specially trains to kill, could you win?
Especially in Noseth, with a force as addition, the gap between those trained to fight and those without became wider. A normal average man in Noseth with average force would at least 1.5 stronger than normal people on earth, a trained man who could circulate their force to precise point like leg would run faster than a horse for a short period of time, as for average nobles who at least knew to train would be able to lift 1000 kilograms over his head.
However, that did not mean that they were invincible, it just means they were stronger than untrain people, a good weapon and new way of warfare could kill them anyway.