Averlanders are not bad for manlings. They're solid in character, stick to their words, and don't put on airs like those nose-in-the-air Reiklanders. And they make the best manling beer in the South! Well, that's not saying much, but you won't choke on it!
Averland is a minor Empirefaction introduced in Total War: Warhammer. It is led by Marius Leitdorf and is situated in the southeastern reaches of the Empire. With Greenskins to their west and south and foul undead to their east they can be in a rather tough spot if they don't find help from their imperial or dwarfen brethren.
The Grand County of Averland is a major and founding Imperial Province that lies directly to the south-east of the Empire. As with the province of Ostermark, Averland has an economy based mostly on agriculture, and the raising of cattle and livestock. Unlike most states in the Empire, Averland contains large stretches of unbroken open plains and while this land is not as fertile as those in Ostermark, it proved valuable as grazing grounds for the infamous Averlander cattle herds.
Averland also has the 'honour' of defending the site of Black Fire Pass, which leads across the Worlds Edge Mountains from the Dark Lands. This is the clearest pass for thousands of miles and as such, is a popular route for marauding Greenskins. As a result of years of defending it, the Averlanders are held in high esteem in the art of siege defences.
When playing as The Golden Order, Averland starts off with the highest Fealty, meaning they will be the first to offer their confederation. Conquering the mountains of Karak Hirn between these two factions, will naturally link your territories upon confederation. This will also put you next to the Von Carsteins, providing a threat and easy access to a target to cut down before they get too powerful. Also, Averland is the easiest way for Greenskins (and Dwarfs) to travel into the land of the Empire, meaning it should be garrisoned accordingly if either declares war.