In EoT each "Kind" (which is like human ethnicity) of Mobian has different and unique needs, economies, history, culture, and goverments, that is the reason Overlanders have the edge as a people group because of they are mainly isolationalists/centralists and are run mainly by a Big Brother style Federal Goverment with strong socialist leanings. There have been more libertarian break off groups however that have skirted and conflicted with Mobians all through out contemporary history even taking over the Dhawman Provance just to get another war/siege with the Underlanders.
Underlanders are a race unique to EoT in that they are like Mutants from X men/ Non-muggles of Harry Potter. Though any living being can learn magic with rigorus practice, the constant exposure to magical forces through generations gives some people innate magical ability. Over the years hard earned skill translates to a snow-balling latent potential in the next generation. Underlanders are an undergound society of spirtualists in a very agressivly secular culture (think of faithless bloodletters like Joesph Stalin/ Mussolini/ Pol Pot and you'll get the picture.) They are hunted down by secret police that constantly witchhunt for "superstious filth". They begin learning to use their natural talents about the same time a Jedi in Star Wars does (two to five) in a series of Half-way houses in a complex underground-railroad (think Harriet Tubman) through the slummy urban fringes of Overland society. They live in large colonies right under the noses of Overland culture. Before the Great War an anti-nationalist group called The Sons of Lazaar built a confederacy that was powerful enough to take over the Dhawman which was a land higly attune to the arcane. They grew to become the first Underlander state in centuries since the fall of the Dark Lord Lazaar. However some Overlanders tried to steal the land (much like Stalin did with Eastern Europe by prologing the blood shed of WW2 to "liberate" the oil-rich Warsaw) from under Mobian noses. It was essentially a war of high-fantasy wizards versus mechanized and modern blitzkriegers versus guerrilla warfare minorties with wildcard intrests. Luckily King Maximillian turned the tide by helping the Latran (Antoine's people) reconquer their homeland. Max signed a peace treaty and diplomacy with the once silent Overland after the liquidation of the Sons of Lazaar (to the shagrin of the various peoples that would eventually fund and forge the militaristic Warclaw movement). Most of the Latran, Renard (Tails's people), and Khani (canines) and nieghboring Wolfpack however were way too thankful to complain and fully self-assimulated themselves into the Kingdom Arkon (the formal name for the Kingdom of "Acorn"). The alliance with the Wolfpack was ambiguous about their policies on beligerancy and stayed rather aloof during the early years of the Great War, much to Max's disapointment, only giving rare and secretive troop-support and some logistical assitance. Underlanders in the meantime lost a lot of their more of their darker number, yet they also became more of a prime target of the Overlander Secret Police.