In the beginning, there were only shamanic practices and the gods worked with these to heal negative emotions like sadness, anger, or apathy. Once time went forward, the gods and spirits developed more and more advanced methods of mental healthcare that improved their methods of improving their followers and helping humanity. However, there was a split in the land of the gods. Some carried forward with psychology despite the issues humanity created for it, while others sought out alternatives.
The goddess Nui stuck with the Diagnostic and Statistical Manual for understanding human trauma, behavior, and life problems. The Maiden Made Of Light read the same books on psychology and self-help as Nui, but found that her healing sun energy did not translate neatly into healing mental illness, as it was mostly effective against trauma and old energies that kept people stagnant. She looked and looked through the libraries of the underworld until she found the books on Dianetics. Curious, she went through and modified the theories until they suited her abilities.
Nui provided people emotional and mental healing as a therapist would, while the sun goddess simply blasted them with the sun’s rays for healing. This eventually began an argument between the two goddesses, as Nui was concerned that the maiden was using improper techniques and working on flawed science. They argued for three days and three nights, until a follower finally came into the hall of the gods to ask them for healing. Confused, they asked him which goddess he wanted help from, to which he replied “Both” and the two deities had an epiphany. Rather than competing, they were able to improve each other’s methods. Nui taught the maiden about her understanding of psychology and wellness, while the Maiden taught Nui about the power of theta, engrams, the reactive mind, and aberration. Nui’s energy continues to help those seeking to improve their mental health and thinking generally, while the sun goddess is good for those seeking to heal specific engrams and traumatic memories.
Ok wtf why are dianetics, a known con, being included in this?
The Sun Goddess uses it because her solar healing method is based on healing trauma from negative memories specifically, so the framework of engram to aberration actually makes sense for her to use. However it should be noted that these methods are not used, but rather the gods have developed their understandings of human trauma and behavior though different books.