Interesting topic! Allow me to bring it back up…
Regarding gods, I’m just wondering why the local origins of the game have been ignored so far. The concept of gods is quite unfamiliar in Japanese culture, but there is the concept of Kami. These are spirits, metaphysical beings, which can inhabit any creatures, objects or places. While people have the duty to appease them, Kami have the duty to perform the function of the object etc. it inhabits. So they can bring both relief and harm alike. They can hardly be depicted, so people make statues of the things they inhabit. Don’t expect my description to be accurate and comprehensive, because I’m even more unfamiliar to this concept than Japanese are with the concept of gods.
Murayama seems to know a lot about western mythology, so I think True Runes are a mix of both. Take the Sun Rune as example: it has some characteristics of Kami, but when Arshtat was talking after she killed Ferid, it was as if an angered Apollon was objurgating his worthless subjects.
In any case, I’m just thinking that learning about Kami could help understanding True Runes.
"Within the four seas, all men are brothers" Shuihu Zhuan