The Emerald Brotherhood was a mercenary company around 1358 DR.
The Emerald Brotherhood was originally an adventuring party operating in Amn, Tethyr, the Thornwood, and the Snowflake Mountains until they were taken into wildspace by mind flayer slavers in 1359 DR. There they focused on destroying the mind flayers as well as the neogi.
The group partnered with Elestam's Crusaders, with whom they fought against both dragons and vampires in the new kingdom of Erlkazar.
The Brotherhood were also friends with the mage Gamalon Idogyr, and they would visit him from time to time at his shop on the Rock of Bral.