Zerig was a fox Captain, and third-in-command of Gulo the Savage's horde of a hundred white vermin, deferential to only Captain Shard and Gulo himself. He was the bait in the trap set for Driftail's gang. During the escape of Sister Armel and Brookflow from the horde's camp, Rakkety Tam MacBurl pinned him to an oak with his dirk, but Zerig apparently survived without grave injury.
After the death of Shard, Zerig was promoted to second-in-command of the horde. He took 50 beasts - half of the horde - and was instructed to attack Redwall Abbey. Freeta, widowed mate of the deceased Shard, struck an alliance with Zerig and was the true brains behind this assault. Freeta and Zerig had in mind to take the Abbey for themselves and leave Gulo behind.
At first, Fargil and Graddu were sent to scout out the Abbey. Graddu was slain by Derron Fortindom, and Fargil boxed by Sergeant Wonwill. Fargil returned to Zerig with a doomsday message and tried to desert, but was slain by Zerig.
Brigadier Buckworthy Crumshaw gave Zerig an ultimatum, that the Long Patrol would meet his horde on the flatlands outside of Redwall. Zerig only sent a fraction of the beasts under his command as a decoy while Freeta with a small band tried to open up a wallgate. This plan was fairly successful, as Freeta gained access to the Abbey, but a charge by the injured Brigadier Crumshaw killed her and alerted the Redwallers.
Captain Derron Fortindom set up a trap behind the open wallgate, Zerig and the 30 remaining vermin took the bait, and were all slain.