Thinking about it. I'm gonna say that rituals aren't truely necessary for a summon. All a ritual does is focalize faith.

Every summoning, in some way is different.

The same primal can be summoned multiple ways for example. One requires crystals the other requires crystals and a sacrifice of the faithful.

"But the ascians taught them how to..." If i lived in a world where primals existed and I was scared Id believe a voodoo man when he tells me that if we kill someone that they will be our salvation through summoning a god to protect my people and myself. Id have to believe that I wasnt killing a friend just for him to die. If i was a terrified beastman/other.

The belief of the kojin is that within luxurious treasures lives spirits. Susano embodies the free living, "revelling", nature of the noble kamis. For generations they have told themselves that reuniting the treasures would please the kami within them. If even one kojin saw that they had been reunited and had one desperate thought of the wol intruding on what is essentially the Kojin la Vatican, it stirred the aether that had been within the artifacts, building exponentially since the moment they were seperated. Thus the Powerp----Susano was born!

Just a thought.