This article or section includes speculation, observations or opinions possibly supported by lore or by Blizzard officials. It should not be taken as representing official lore.
Due to Gilneas' isolationist policy, it is possible that the Brigade was formed by Gilnean dissidents, and the pro-Alliance rebels lead by Darius Crowley. Although, how these men would have escaped the Greymane Wall is a mystery.
It could also be that the members of the Brigade, were some of the villagers of Pyrewood, as new information suggests that Pyrewood was originally a Gilnean village. This could explain their existence, as Pyrewood was not isolated behind the Greymane Wall.