Werewindle

Werewindle, also known as Rawg and the Day Sword, is the golden-colored sentient spikard blade that was at one time wielded by Brand. Like its twin, Grayswandir, Werewindle is inscribed with portions of The Pattern of Amber. This makes both swords particularly useful against creatures of Chaos.

In Coming to a Cord, Frakir informs Luke that he might be able "to draw enough energy through Werewindle to destroy a world".

.

Etymology
The name Werewindle means "Day Sword". Even the Shadow Earth bears a reflection of the legend which is Werewindle in the form of a Scandinavian king and swordsman named Aurvandill who cleaved enemies' shields with his sword; the aur portion of his name means "daybreak", and the vandill portion of his name means "sword". Other Shadow permutations of the name include Auriwandal and Horvendel.