The Gods of Fire and Sky co-exist alongside the Lunar Way in a pluralistic religious landscape in the Lunar Heartlands. Rituals honoring Yelm, Dayzatar, etc. are dominant in formal, elite, and rural sacrificial contexts, while the Red Goddess, Seven Mothers, and other Lunar cults gain traction through devotional practices that appeal to broader social groups, including farmers, women, soldiers, etc.
By 1625, the Lunar Way is predominant in the Silver Shadow, where they are the focal devotion for about half the population. In other areas they are not as significant in daily devotion. For example, less than a third of the population of Kostaddi have their focal devotion on the Lunar deities – they are acknowledged and worshipped, but Lodril, the Grain Goddesses, Shargash, Oslira, etc., have more daily relevance.
But co-existence is key to this. And a lynchpin of that co-existence is the Yelm cult. Yelm is the traditional ruling deity in Peloria, and Lodril, Dendara, Shargash, Polaris, etc., all serve him. However the Red Goddess is acknowledged in the Lunar Heartlands as the reborn daughter of Yelm and her daughter – the Red Emperor – is the supreme priest of Yelm in the Lunar Heartlands. The Red Emperor requires that rulers such as satraps join the Red Goddess cult to receive consecration into the Yelm Imperator cult.
Yelm and the Red Emperor unite both the traditional solar worship of Dara Happa AND the Lunar Way in their own person. If you assume that the Yelm cult in the Lunar Heartlands is in conflict with the Red Goddess, you are making a serious error. Of course, you wouldn’t be the first outsider to make that error.
Always remember the tie between the emperor and the Yelm cult. All of those reforms mentioned in the Fortunate Succession had the support of (or were even driven by) the emperor. And in 1625, the Yelmite emperor is the Red Emperor, and that has been the case for many centuries.
I’m a little confused by the ambiguous initiation rules. For instance, can women initiate into Yelm? It doesn’t say not. Similarly, do men initiate into Dendara? It’s not clear, only requirements for said initiates to have the right parent in the cult. There is a sense by reading between the lines that neither case is allowed or happens, but nowhere is it said definitely. Is this to allow PCs freedom to try something different, or a case of there being rare exceptions permitted?
Dendara follows the same pattern as Ernalda – men and women may initiate, but only women may be priestesses.
Yelm does not require that a lay member be male (remember that’s what drives initiation). As a practical matter, most lay members are male, but that’s custom rather than religious requirement.