The Hawk leader fought in a war in the Slough of the Disunited Planets.

The Hawk leader teleported the Brigadier to the battlefield, declaring him as their Warkeeper-elect, and the Tenth Doctor as his "fool". He flew the Brigadier and the Doctor over the battlefield, leading them to the Warkeeper. As the Warkeeper was weak and dying, the Hawk leader, along with the other Hawks, were temporarily frozen. He eventually woke up again, and followed the Doctor and the Brig. He encountered Lilly, and presumably killed her. He then took some troops to attack the harpies, but they escaped. The Hawk leader began to falter as the Warkeeper had been killed, and he no longer had a controller. He flew, along with the other Hawks, the Doctor and the Brig, back to the Warkeeper's room, and commanded the harpies to stop. However, as Michael Yates was now the controller of the Hawks, the leader had no choice but to follow him to Upper Wardleswick.

After the crown was shot off Yates' head, the Hawk leader commanded his troops to locate the sniper who had fired the shot. He brought the sniper, who was a clone of the Brigadier, up to Yates and the harpies. After Yates commanded the clones to dissipate, the Hawk leader died too, as the Hawks were also cloned creations. (COMIC: The Warkeeper's Crown)

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