The Red Goddess provides Chaos Gift to many Lunar cults, including initiates of her own cult and to senior priestesses of the Seven Mothers (but also to initiates of Danfive Xaron, priestesses of Deezola, Rune Lords of Hwarin Dalthippa, initiates of Yanafal Tarnils, and Yara Aranis. As we all know, this spell temporarily grants the caster with a random Chaos feature and permanently taints the caster with Chaos. So let’s assume somewhere less than 1% of the Lunar population is tainted by Chaos, but that percentage is primarily in the ruling class or its henchmen.
Remember that a Chaos feature is much more than just a cool power – it is something that warps and mutates the recipient. Often it results in mutated horrors, but even when beneficial the results can be inhuman. People with features too smooth, uncanny valleys, exaggerated or grotesque body parts, and so on. But also those gifted have the sensation of wielding blasphemous power ripped out of the cosmos. Now 99% of the population have never experienced Chaos Gift, but that less than 1% are tainted by the experience. Many are Illuminated, but many are not. Needless to say this likely has some cultural effect.
How would a high chaos rune affinity affect someone’s personality? I don’t think Chaos has a single personality. It is corruption, entropy, and evil. It is formless, emptiness, the void, or the abyss. It is the antithesis of the cosmos – the complex system we know as Glorantha. Most normal creatures are instinctive repelled by Chaos and most mortals find it terrifying and wrong.To reference the other roleplaying game, Chaos triggers SAN checks, sanity loss, and cosmic horror.
This aspect of the Lunar religion is often papered over by cults like the Seven Mothers but it is there at the heart of the Red Goddess cult. She is Life, Moon, and Chaos after all.