Ruggum was a male Dibbun mole of Redwall Abbey who was the best friend of Bikkle the squirrelbabe. Together, they ran away from Redwall so they would not have to take a bath, not caring about the frantic search that the Redwallers had instigated upon discovering their absence. After spending a long, dark, and terrifying night in Mossflower Woods, the duo began wandering around in a vain attempt to get back to Redwall. Ruggum correctly sensed a spring storm approaching; when the rain began to fall, the two frightened Dibbuns sheltered themselves in a large oak tree that had a door at its base; unknowingly, they had discovered the long lost Brockhall. The pair were scared even further upon the grisly discovery of the carcasses of King Sarengo the ferret and Berussca the adder, within the tree; fleeing into the rain, they were found by Skipper and Log-a-Log Groo, who took them back to Redwall. Ruggum brought with him a gold pawring he had discovered in Brockhall; the script upon it later proved instrumental in solving the hidden location of Brockhall's rear entrance.
Ruggum was very rebellious, argumentative and stubborn. He was a possible leader of the Dibbuns Against Bedtime. Later he and Bikkle were trained as Bellringers for the Abbey.