Adiya was a demon.
She had the ability to take on human form while hiding her true nature. Her real form was a torso carried upon limbs of tentacles, each of them covered in hundreds of mouths. Three horns portruded through the top of her head, and in lieu of a jaw, a gaping orifice pulsed at the bottom of her head.
Disguising herself as an Umbaru female who was supposedly the wife of Guwate'ka, Adiya revealed herself to Benu, a Witch Doctor. She had sensed his doubt and had been drawn into the jungle. On the day before an Igani Bawe, she told him that the spirits of the Unformed Land were uneasy. That they said that there was nothing in the Umbaru that was unique or worth celebrating. That the Umbaru were blind. She further claimed that the high priests were using the Igani Bawe as a means of controlling Umbaru society. Benu was uneasy, but did admit that he had seen things in the Unformed Land that had made him question his dedication to the Igani. Adiya told him that she had come to Benu in the hope that he might change the Umbaru's ways.
The following day, Adiya came to Benu during the Harvest of Souls, despite being forbidden from being there as she was not a Witch Doctor. Having seen the results of the Harvest, he came to accept her claims as being true. However, they were captured by Tribe of the Clouded Valley Witch Doctors. Both of them were led to the tribe's home village where they were to be sacrificed. Adiya mentioned that the Umbaru were forbidden from carrying out cannibalism—a great sin in Umbaru society, for one who did so would become kareeb; damned by the spirits. She claimed that these were stories crafted by the high priests, and that her husband had heard stories of eating Witch Doctor flesh being a path to godhood. With this power, they could reform Umbaru culture. In truth, she sought to torment Benu, as he would be so distraught by his actions, she would be able to feast on his spirit years later.
Whatever the case, when the tribesmen came to take them to be sacrificed, Adiya killed them and led Benu out of the hut. The Clouded Valley tribesmen were stunned, as this was far from normal behaviour in an Igani Bawe, where captives were honoured to be sacrificed. She bit into a captive's heart and bristled with power. She bid that Benu do the same. However, he refused, causing Adiya to lash out at him, calling him a coward. She shot bolts of energy into Benu, temporarily incapacitating him. She then turned her attention to the Clouded Valley tribesmen, killing scores of them and devastating their village. Benu got to his feet and battled her, and while he was able to kill Adiya, the wounds she inflicted on him ensured that he died himself moments later.