Rikumaru

is one of the Nara clan's deer.

Personality
Rikumaru does not seem to be afraid of humans like most animals and he did not flee during Shikamaru's and Hidan's fight.

Appearance
Rikumaru looks like a normal deer with light brown-coloured fur and dark brown-coloured eyes. He also has two big black-coloured horns on his head like a normal male deer.

Hidan and Kakuzu Arc
Rikumaru stood beside Shikamaru's side when he swore to Hidan that his clan would keep him buried there for all eternity. He later followed Shikamaru to the edge of the Nara clan forest.

Trivia

 * In the anime, Rikumaru stood by Shikamaru's side while he buried Hidan. In the manga, Rikumaru is not seen until Shikamaru meets Sakura, Sai, and Pakkun at the edge of the Nara forest.
 * Antlers, like his, are a key ingredient in a variety of medicines.