Veil Sixclaw
Veil Sixclaw is the ferret son of Swartt Sixclaw in the book, "The Outcast of Redwall" by Brian Jacques. In the book, Veil has to choose on whose side to fight - against the kind Redwallers who cared for him as a baby, or against his true father.
Birth
Veil was born to Swartt Sixclaw, the evil warlord in the book, and Bluefen, Swartt's wife. Swartt cared very little for his wife (and Veil), seeing that it was tradition for a new Warlord to receive the old Warlord's daughter as a wife. Swartt had killed Bluefen's father, Bowfleg, to win the horde for himself.
Coming to Redwall
Veil came to Redwall due to a battle near the Abbey itself. Swartt, hunting down Sunflash the Mace, decided to go down the main path in Mossflower Woods. Skarlath, Sunflash's friend, sees Swartt and his horde going down the path, and flies ahead to warn the Redwallers. After meeting with them, a squirrel devises A Plan to gather an army of squirrel archers and otter slingers - what he called an "invisible army". The army engaged in battle with Swartt's horde, and pushed them to the west side of the path. In the haste to get out of the line of fire, Veil's elderly caretaker drops him, and dies. Veil is then found by the squirrel after the battle, and is taken back to Redwall.
Sources
"The Outcast of Redwall" by Brian Jacques