Uggo Wiltud was a plump young male hedgehog resident of Redwall Abbey, and likely a distant relation of Pinny, Twoggs, and Drogbuk Wiltud. He was a bit of a glutton, like all the Wiltuds, and could not swim.
Uggo got into serious trouble with Abbot Thibb when he stole a huge marchpane-covered fruitcake and ate the entire thing himself; he was sentenced to kitchen labor for three days. While he was experiencing a stomachache after gorging the cake, Uggo had a vision of Razzid Wearat and the crew of the Greenshroud coming to attack the Abbey. Relieving Uggo of his kitchen duties, Jum Gurdy the Cellardog took the young hedgehog with him on a quest to seek out Wullow, an old otter who reportedly knew something about Wearats.
During this journey, Uggo was captured by Snaggs' Gang. While he was imprisoned, he met Posybud; the two of them were rescued soon after by Jum and four of the Whoomers. While they were sailing away from Snaggs on a makeshift logboat, a storm blew up; Jum was washed off the log, and the two hedgehogs were intercepted by the Greenshroud.
Uggo and Posybud were taken aboard the wheeled ship; there, Razzid Wearat confronted Uggo, demanding directions to Redwall. As he was hopelessly lost, Uggo could not answer the vermin's questions. Angrily, Razzid locked the two young hogs in a storeroom; however, the duo managed to outsmart the none-too-bright vermin crew, and escaped overboard, again aided by the Whoomers, who towed them to shore.
Fleeing from the vermin, Uggo joined up with the Fortunate Freepaws and the Guosim, later meeting up with the Rogue Crew and Long Patrol. The band made its way back to Redwall, getting there just before Razzid attacked the Abbey. While the Guosim, Rogue Crew, and Long Patrol battled the corsairs on the grounds, Abbot Thibb gave Uggo the the sword of Martin the Warrior, and instructed him not to let any vermin inside the main building.
When Razzid and Badtooth barged into the kitchen storeroom, Uggo was waiting for them; he slew Badtooth on the spot, but fumbled the sword and lost it. Razzid began to torture Uggo with his trident; puncturing his foot to the ground. However, Posybud and Jum slew the wearat, and Uggo survived the encounter.
Whether his foot fully healed or not is unknown, as well as the future of his relationship with Posybud.