Heather Nightrudder is a black-furred ottermaid who first appears in Defenders of Redwall.
Heather has black fur and green eyes, and always wears a claw necklace. In her first appearance, she wears a simple, light pink dress, about knee-length and with elbow-length sleeves, as well as a woven yellow paw bracelet.
In Stormy Friendship, Heather's outfit has changed to a brown shirt with a green one beneath, with a metal mail skirt and pointy arm-guards. She has a black hood and brown mask that covers the lower half of her face, purple leggings, and tall brown boots with mail tops and metal kneepads, with earrings.
In the third book, Heather wears a short red tunic and indigo leggings under a leather and metal breastplate, as well as a leather skirt over her mail one from the previous book. She also still has her hood, mask, and arm-guards, but has added metal shoulder guards and tall leather boots.
In her first appearance in Defenders of Redwall, Heather is rather sweet and kind, and not much of a fighter. She is very sly and a good actor however. By the next book, however, she has changed a lot.
The next time Hiccup and the gang meet her, in the second book, she is very different. She is hardcore, in a word, and will stop at nothing to get her revenge. She is more easily angered, and when she is angry, goes berserk. It is not quite Bloodwrath, she just can't think clearly and can't control what she does very well. In a good mood though, she is still very nice.