The Brotherhood is one of the human Successor Kingdoms of Kings of War, much like Basilea and the League of Rhordia. The Brotherhood is something of a mix of Bretonnia and Azeroth, although the models pictured in the book are from Deus Volt by Fireforge Games, implying a warrior monk theme.
The Brotherhood is said to have emerged from the ruins of a kingdom whose name is lost to history. When Valandor defeated Winter and flooding covered the world, their kingdom was largely drowned by the rushing seas. What once was a vibrant land-based empire was reduced to scattered islands and underwater ruins now called the Forsaken Isles. Despite this devastation, it was their forces who protected Valandor as he tried to reduce the damage wrought by the flooding from the remnants of Winter's army.
It was also Valandor who taught the ancestors of the Brotherhood to use water magics and summon water elementals. When Valandor sacrificed himself to save much of Mantica, the survivors of this lost kingdom vowed to pledge themselves and their descendants to the eternal fight against evil. To aid in this quest, they built a large fortress facing the Abyss that stands to the present. Their forces spread across Mantica in small numbers, taking on different vows and fighting styles depending on where they went. These became the different orders that compose the Brotherhood today.
The Captains' Council oversees the various orders of the Brotherhood. They are stationed at the fortress near the Abyss. Their main chamber houses the armor of great warriors of the past in a circle around the amphitheater. Benches sit in front of these that any member of the Brotherhood may sit on when the council is in session. In the center of the room is a main stage where the captains themselves sit around a central, empty seat reserved for Valandor if he ever returns.
- Order of the Abyssal Hunt: A questing order. These knights specialize in fighting large monsters, such as dragons, lamassu, or even the occasional neutronium golem. They are one of the more numerous in number orders, although not nearly on the scale of the Order of the Brotherhood. On the tabletop they get some pretty hefty stats good for monster hunting, and even get Vicious specifically when fighting monster units.
- Order of the Brotherhood: The most basic vows a knight may take. New recruits from the peasantry begin in this order, often on foot fighting alongside the Villein peasant levies. They are the most numerous order with many remaining in this order for life. They are generally stationed near the Abyss in order to maintain the Eternal Watch.
- Order of the Forsaken: The order stationed on the Forsaken Isles. Whereas most orders ride into battle on horseback, the Order of the Forsaken ride on monstrous beasts. Many ride on pegsasi, but some members of the order also ride on large aquatic steeds. Their primary focus is on guarding the underwater ruins of their former kingdom from pillagers, but they also send small compliments of their forces to aid other orders in larger battle campaigns.
- Order of Redemption: Another questing order. The knights of the Order of Redemption take a vow to hunt down the agents of the Wicked Ones wherever they may be. These knights all wear the Armor of Tides, an armor set imbued with water magic that both protects them and heals their wounds. These suits of armor are placed in the Captains' Council chambers when their owners fall in battle. Young recruits who feel a compulsion to touch one of these suits can be chosen by the armor to bear it, signified by a magical sign for the order to see upon doing so.
On the Tabletop
Tactics can be found here: Kings of War/Tactics/Brotherhood
If you're looking to field a large amount of cavalry, this is the army for you. They have some infantry support, but cavalry is where this army shines.