The Beastmen of Kings of War, although notably they aren't evil in the setting. They were one of nine armies added to second edition in the Uncharted Empires supplement to allow Beastmen players to field their armies in Kings of War. They also have a number of units not found in the army, but more in tune with the models of House Teknes of Wrath of Kings or the Thornfall Alliance of Hordes.
Kyron was a Celestian known as a friend to nature. When the Fenulian Mirror was shattered, Kyron split in two like the other Celestians. His Wicked One and Shining One sides both retained the name Kyron, both seeking to continue to watch over the creatures of nature. The wicked half was known to be cunning and cruel, while the shining half was known for his kindness and bravery. It is said the two halves, instead of engaging in physical combat, argued incessantly with one another about the proper way to guide the natural world.
Eventually they decided to settle their differences by reforging the beasts of the world into new creations to vie with one another. Dark Kyron, as the Wicked One was designated, worked with Garkhan the Black to create the orcs. When Brave Kyron, as the Shining One was designated, saw this new horror, he gathered the souls of those sacrificed in their research and reshaped them into the beastmen of the Herd.
Enraged, Dark Kyron sowed mistrust of the Herd among the human nations, seeking to destroy them. Many of these reborn souls fled to the sea, transforming into forms suited to hide among the waves. They hid under the seas for centuries, only venturing back to the surface after the defeat of Oskan. Once they reached the surface they discovered that the two Kyrons no longer walked among mortals, but were said by their surface-dwelling cousins to now endlessly chase one another through the skies as part of the Great Hunt.
The Herd seek to protect the natural world from those who seek to destroy it, particularly the cursed sons of Garkhan the Black and Dark Kyron. To this end they are often seen fighting alongside the denizens of the Trident Realms of Neritica. Humans tend to be distrusting of them to the present, but it is not unheard of for them to fight as allies as well.
On the Tabletop
Tactics can be found here: Kings of War/Tactics/The Herd
The Herd are very strong in games with a lot of terrain. Their army special rule grants most of the army the pathfinder special rule, meaning they do not take penalties from terrain. This means they can march normally and charge through whatever is in your way without that pesky -1 to hit.