Walt was a male mole in Foremole's crew at Redwall Abbey, and the brother of Doby. The grandmother of Walt and Doby found the step marked W (or M upside down) in an ancient castle and brought it whole, without breaking it, to be used for the stairs between Great Hall and Cavern Hole.
Walt and Doby helped the mole crew turn over the step that contained the entrance to the sepulcher of Martin the Warrior.
Not to be confused with Wandering Walt.