Brull was an Acamarian Gatherer in the 24th century. He was the leader of the outpost on Gamma Hromi II. He had two sons, one of them almost the same age as Wesley Crusher.
Brull was one of several Gatherers who ambushed a USS Enterprise-D away team in 2366 with Regalian phaser rifles on Gamma Hromi II. The Enterprise had sought out the planet, and the Gatherer camp there, as part of a peace overture from Acamarian Sovereign Marouk.
Marouk was attempting to re-integrate the Gatherers into Acamarian society, despite over a century of failed attempts to do so. After speaking with Marouk, Brull was able to arrange a conference between her and Chorgan, the Gatherer leader, that ultimately proved successful and allowed an agreement to be reached. (TNG: "The Vengeance Factor")