Rainwillow

Rainwillow is a lithe, sleek, broad-shouldered, muscular silver and white tabby tom cat, with icy blue eyes and piercing sharp claws.

Enchanted Willow
Rainkit makes an appearance when playing with his litter-mates.

High Tides
It is revealed he is evil.

A Battle Of Flames
He dies to Sorrowrain in this book, after he kills his sister, Gloomflower.

Trivia

 * He met up with Minnowtail, Fernmist's daughter, over the border, he ended up killing her by drowning her. They had Windpaw together, who dies of food poisoning.