Cormac McTaff, the Master Armourer, forged these weapons to present them as a present to Bran A'Karris. After their forging, they were taken from Cormac by The Gloag, who performed a magical ritual over them, imbuing them with power.

Bran was later assassinated while journeying to Cormac's storage caverns to collect a particularly fine suit of chainmail. 

No-one knows why Bran was killed, but Cormac survives to this day, the assassins knives failing to kill him.

The current location of A'Karris' blades is unknown, having been carried off by the killers while Cormac was unconscious.
 

Abilities
Indiviually, the blades have no offensive powers. Weilded together they double the bearers physical attack rate, while halving the chance of inflicting a wounding hit.. 
Likewise, defensively the blades are inert alone. When wielded together they double the bearers physical parry rate, while halving the chance of a successful parry.

The bearer is immune to the first mind affecting spell used on him in any one combat, being forced to fearlessly attack the source of such magic instead.

Any evasive maneuvers are also 50 percent easier in combat, due to the rate of movement available to the bearer. Like the other powers, this only comes into effect while both blades are used together.

While separate, the two swords each radiate a weak magic aura. Together, they radiate a very strong magical aura.