The organization was not called Light's Embrace. Although the Twins had learned from the fungus's memories that they—or rather, the "Swarm"—had been called the Photonic Symbiotic Fungus during the Pre-Epoch Civilization, they had not yet considered establishing a church.
What they created was a simple mutual-aid organization. Using their power of prophecy, they foresaw disasters in certain places, then arrived and used their power of retrospection to observe their causes, resolving the problems at their roots.
The Photonic Symbiotic Fungus was a special symbiotic fungus from the Pre-Epoch Civilization, intended to be spread among all humanity. It was not truly a fungus, nor any kind of "fungus" that could be clearly classified on Terra. In a sense, it could be called a biological nanomachine. By absorbing light radiation, it could provide humans with energy, and its energy conversion efficiency exceeded fifty percent.
Humans who received the Photonic Symbiotic Fungus would theoretically undergo a comprehensive transformation: their bodies could absorb vast amounts of metal and rare elements, synthesize mycelial channels within themselves, become immune to all diseases and toxins, and have cells that could scarcely be destroyed by outside forces, only forcibly displaced.
Because they could directly use photoelectric conversion to power their cells, Photonic People could live in space without sleep or rest. Even at the edge of the solar system, they could accumulate energy from faint sunlight and enter hibernation. Photonic People did not need oxygen—or needed very little of it—their lifespans could reach several centuries, and they could easily extend them further through life-extension surgery.
The only problem was that, while symbiosizing with a host, the Photonic Symbiotic Fungus invaded the nervous and cognitive systems. This was to ensure that its energy could be transmitted to every corner of the body, strengthening the human physique in every respect.