From deep within the Fortress there is an inhuman roar- discordant and unnatural as it rumbles through stone and wood and iron; those closest may be overcome with a wave of nausea or an icy chill in their core. From the depths of the caverns there is the hot wash of air moist with the scent of rot; of curdled blood. Wet, fleshy footsteps lumber to the cave's entrance, shades crackling with ash and vicious glee spill from the caverns like so much blood; loosed from their confines to clear the field of any that are not of the Crows.

Or.

Anyone that is moving.

Behind comes the shape of a golem Twice as tall as a man and thrice as thick, swinging meaty, dripping hands into whatever blocks it's path. At the first sign of movement it bellows once more- and charges.