Kikono

The Kikono were a religion built around the Temple of the Skies in the Chikyu Nation. They praised The Aeratiras and their powers since they were first formed 13,000 years ago with the arrival of mankind to Yatan. Their first evil intent rose 150 years ago. The Kikono was shaped into the opposite of it once was, it wished to destroy the Sento for bringing to Yatan, something they claimed the Aeratiras willed against (they still worship The Aeratirairas) because they did not see the Three Brothers as real Aeratira. Kyokku's Grandfather was responsible for creating an infestation that was intended to destroy the Sento-ki by siphoning all of their mana. After the Infestation program was shut down, they started a Source program. This one also proved to be a failure when it was passed down to her father. After that, the Kikono began research on Sprites and Gemini.

Kyokku has led the Kikono by her Grandfathers will to destroy the Sento. To do so, she brought back the Source and Infestation Projects, as well as starting a third: Sprites. The Kiko were sent across Yatan to scour the land to gather back the Sources they had lost, to  Limos. Her plan was aided by Somnium who promised to guide her to defeating them.

The events started when Somnium convinced Zade to follow his will. Eager to show how her father was a failure,  agreed. He manipulated her to do all of the following, without ever actually aiming to end the Sento.

met with her old friend, Zade, one of the elders of the Shadow Nation. She manipulated him into attacking the Fire Nation. She told him how the other nations untrusted him, and when war broke out they would be the first to fall. Zade cared for his people and wished for their survival. He agreed with Kyokku and followed her orders. To make the Shadow Nation's army attack, Zade went to his son Kaylen. Kaylen was a man filled with hatred and was the head of Shadow military. Over the course of a year, Zade had made Kaylen despise the other Nations while thinking the Shadow to be superior. He came to believe if he attacked the Fire Nation, the other Nations would not help them. In fact, if they did, Kaylen believed he could beat the other Nations. Zade used this manipulated nationalism to convince him to attack.

When the Shadow Nation attacked, it destroyed nearly half of the Fire Nation. The other Nations did come to aid, but fighting the Shadow's military was no easy task. They pushed them back to their island but lost a large portion of their armies doing so. They then followed them back to the Shadow Island and razed their villages, attacking them directly.

Kaylen gathered his people, two thousand citizens, and brought them off the island to an unknown location. He kept them safe. Kaylen would think Zade had died by this point, but Somnium came to him. Somnium had guided Kaylen into creating the Eritomoru by recruiting exiles across Yatan. They all wished vengeance on the Sento much like Kaylen. In this recruitment, many Kikono Operatives were put behind the Eritomoru's lines. Ones like Ordis and Drayon.

Over time the Kikono secretly guided the development of the Eritomoru. It was Somnium who caused it's upbringing, and Kyokku who promised Zade to be its eventual leader. Kaylen led the Eritomoru to attack the 7 nations in unison. They struck the capitals, and devastation was brought to homes and innocents alike. Kaylen only ever wanted to hurt the Sento, but the Exiles intended to do full harm.

After the attacks, the citizens had been spread across the lands. It became knowledge that no place was safe, as Eritomoru raids continued on smaller villages. Citizens left their homes to try and find hidden residence, and some tried to get off the Island. Zade had made a village for just that; to help fleeing citizens escape.

Reviving The Aeratira Master
The massacre across Yatan was well intended by Somnium, who knew the exiles would murder innocents. When a life is taken, their mana is released into the air. With all the deaths, the mana infused air in Yatan grew stronger. Somnium wished for it to be dense enough to where he would power the combining of the Sprites, the Sources, and the Aeratira's body.

Kyokku followed Somnium's orders and was told to convince Zade to make a village for citizens to flee to. Kaylen became aware of Zade's village but never made the Eritomoru attack them. The goal of the village was to gather up innocent people and send them to an island to be killed to gather mana. Zade knew this, Kaylen did not. When people stopped showing up to the village, Kyokku initiated a final step to her plan. She made her Kikono agents within the Eritomoru attack. After the betrayal, the Eritomoru was left in ruin. Zade was shocked, believing he would get control of the Eritomoru.

Kaylen, Elenai, and Izokah had later gone to the Temple of the Skies, the Kikono's base of operations, and confronted Somnium. Zade showed up to try and save them but he was killed by Somnium.

In a final effort, the Sento-ki played into Somnium's trap. They attacked and Somnium ended up bringing Kaylen to be captured. He now has the Sources, Herald, and a Sprite. He only requires Sprites.

Infestation
This project led to the discovery that all living things have mana, as the infestation had killed hundreds of innocent people. It was deemed a fail and the Kikono had to kill everyone in the facility, an extra hundred lives of the works, to prevent the spread of the infestation. It was locked away in the abandoned facility but never destroyed.

Source
The Kikono temple houses the remains of three past Aeratiras: Limos, Calypso, and unknown others. They wanted to understand how The Aeratiras had died, because they believed them above godlike, so they experimented on the remains. They found living energy inside of each of the Aeratira and contained each living energy in a vessel. They knew these to be Sources but expected them to be gone. Using this new living energy, they hoped they could harness it to overpower the Sento. Their test subjects were unstable when imbued with the Sources, and the Father abandoned this project. It was started by the Grandfather.

Later, Kyokku, the Daughter, brought back this project to use in conjunction with a plan surmised with Somnium. When releasing the Sources, many of the subjects were somehow still alive and escaped; notably The Prowler.

Sprites
Not much is known about their research of the Sprites, but it was never completed due to their downfall. The only people who know about Sprites  Kikono, Gamma, and a few select individuals. The Sprites were never public knowledge because Aeratiras tirelessly protect them from being gathered to resurrect the Alpha-Sprite.