“Brann, the Unbent Blade” is a unique unit of the Cabal.
Brann, the Unbent Blade is a unique Centurion Cabal unit armed with a Cabal Bronto Cannon.
They largely stay on the wall and fire down on the Guardian. After a short while they will head toward the far end of this section.
It helps to use the turret's command room below it for cover or to take cover behind the raised portions of deck.