Kokopo (ココポ) is a Hororon Bird that Rulutieh rides.
Kokopo's head is covered in white feathers, the body is dark gray and the tail is red with a black arrow pattern. A black, red and white tuft extends from her head. Her saddle is red with brown straps that secure it in place. She chirps like a pigeon mixed with quail sound.
Kokopo is pack animal that Rulutieh uses to travel around and serve as battle companion. She has the ability to read its master's emotions. Kokopo is very protective towards Rulutieh, and doesn't stop until she beats her master's enemies to a pulp. Even Rulutieh is unable to stop her when she goes berserk.
According to Rulutieh, Kokopo doesn't easily trust others and always keeps her guard up near other humans. In game, when Haku accidentally bumps to Kokopo, the bird affectionately rubs her head against him. Rulutieh states that she has never acted this affectionately towards others.
In the game, Haku first meets with Kokopo when he accidentally bumps into her. Kokopo stares at him, begins to rub her head against him, chirping happily. When Haku begins to walk away, Kokopo start to follow him. He sprints to get away but she catches up to and happily sits on the top of him. Haku begs Rulutieh tell Kokopo to stand up, but the bird refuses. Only once Kuon arrives does Kokopo finally let Haku up. According to Kuon, Kokopo refused to let go of Haku because she likes him very much. The reason why Kokopo didn't listen to Rulutieh's pleas was because Kokopo considers her a friend, not a master.
In anime, Haku mistakes Kokopo for a talking bird, and compliments her very beautiful voice. Kokopo's blushing reaction suggests that she likes Haku very much at first sight. During their journey to the capital city (before they were stopped by Nosuri), Kokopo affectionately nuzzled Haku. To Haku 's dismay, even Rulutieh can't stop her and she's never seen Kokopo this affectionate towards other people. Kokopo is very protective towards people she cares. For example when Maroro tried to sit between Haku and Rulutieh, she kicks Maroro away. When the bandit leader spits at Haku, Kokopo attacks the bandits in a rage and chases them away.
Because of this, Mozuno the bandit leader called Kokopo "Nugizono Kami" (in game only). When the group meets Mozunu once again when he tries to rob somebody's home, the bandit screams at the sight of Kokopo and runs away. The group chase the bandit to their camp. Mozuno shouts not to let Kokopo near them because she is a Nugizono Kami. Mozuno said that Kokopo was a demon, a god of misfortune, the devil because of her size and colors. Rulutieh defends her by saying that Kokopo just an normal Hororon Bird. This answer went into blaze of debate, Mozuno explains that a normal Hororon bird was smaller and the colors are far more vivid. Hearing this explanation, Haku asked the group if what Mozunu said is true, which end with silence from Kuon and Rulutieh.
Kokopo considers Rulutieh to be her friend and family, rather than her owner. She willingly fights for and defends Rulutieh if anyone is ever rude or disrespects her.
Kokopo likes Haku very much. Rulutieh is dismayed as she was unable to stop her from crushing Haku. Haku is the only person she shows affection to beside Rulutieh.
Kokopo first showed a natural hostility towards Mukkuru when Aruruu and Kamyu visited Yamato. In the end, the two animals reconciled and ate together, along with sleeping together. When Mukkuru left for Tuskuru, Kokopo was very sad and even waved goodbye to her friend. She attempted to meet and chase him when she spotted him in Tuskuru but was instead led to Munechika's camp with the supplies. This event happened in anime only.
- Despite being a Hororon bird, she can't fly.