Ascrod and Vannan were the two who were chosen to infiltrate Redwall Abbey and steal the famous tapestry of Martin the Warrior, planning to take it back to their mother, Queen Silth. They succeeded, and on the way out Ascrod killed the kindly owl Nutwing. However, their treacherous brother Mokkan betrayed them and took the tapestry himself, leaving the remaining Marlfoxes to have a drawnout battle the Redwallers.
Ascrod was the one who figured out to get through the Abbey walls by sliding his axeblade through the gate to lift up the latch. Right before the final battle he was killed by a giant arrow that was fired by Badgermum Cregga.
- Read more about Ascrod at the Redwall Wiki.