Upas

 is a bear +Anima of the lost Tooa Tribe, and was a friend of Senri's father Riiya.

History
When Senri was young, Upas was on good terms with him and would teach him life lessons.

Upas went with Riiya, Senri and some other Kim-un-kur to hunt Amurui. When Senri was injured, Upas tried to fight off Amurui while Riiya took Senri to safety, but Upas couldn't hold his own and was injured. He was saved by Riiya, and then witnessed Riiya go mad and attack Senri who killed him in defense.

Plot
Upas uses his bear Anima to scare off the approaching Astarian soldiers, but Senri's Anima reacts and causes him to fall unconscious so Upas accompanies Si Mukar to retrieve Senri. Back at the military base, Upas watches over Senri, and once he awakens is disappointed to learn that Senri's memory issues haven't disappeared.

Upas later requests to be able to take Senri on a trial, which Si Mukar grants permission for. Knowing that Senri has a piece of Amurui's Anima inside of him, Upas uses the opportunity alone with Senri to try to kill him, however he is interrupted by Cooro and Nana, and the appearance of Amurui's cub. After Senri kills the cub, Upas starts his fight again, but the situation is calmed by Husky.

Later, Husky asks Upas about a way to travel to Sailand. Upas agrees to unseal the path on the condition that Husky take Cooro, Nana and Senri with him.