Then something happened, some sacrilege occurred. We do not know what or who did it. Maybe it was SuVee that finally decided to setup shop on the "virgin" world. Maybe Guristas/Jove/Competitor/etc made an attack on a holy site and took something of great value to the Achurans. In any case the Achurans decided that in order to prevent future sacrileges, protect their home, or get back what was taken they must take to the skies.
Unless it has been retconned, the Rod of the Creator was stolen from Achura, which is why the (NPC) Celestial Imperative was created by the temples and Achur officers from the Caldari Navy: to find it themselves.
The Caldari are militaristic, ruthless and hypercapitalistic. Do your job, or fall into nothingness. How on earth does an intensely spiritual lot fit in with them?
Intensely spiritual does not necessarily mean nice or pacifistic (hello, Amarr).
The Ceremonial Brush is a disturbing example.
The
White Songs were originally important to Achur because they were a symbol of the Imperial line of the Achuran Empire that, I think, evolved into a symbol of all of Achura after the Empire ended - they're still held in deep reverence. That makes me think the Achur
seemed to have a similar planetary empire to the ethnic Caldari's Raata on Caldari Prime.
When they met, there's a very good chance both sides saw a bit of themselves in each other and decided to work together instead of the typical violence that happens when anything called an empire meets another group. (Of course, the Raata was over and done by then, and I don't know if the Achuran Empire ended before or after meeting the Caldari.) Or, the Stargazers (Hi!) could have simply agreed that their future lied with these people from the stars. And, the Caldari by that time had experience with peaceful first contacts with other worlds as a partner with the Gallente in the Federation's explorations.
When the Caldari fled to create the modern State, the Achur - who were already conveniently living in The Forge - probably had little trouble deciding to help/join their 'proper' cousins that they met first instead staying with the wildly chaotic Federation that they'd had less contact with. (That also depends on if the Achur actually
did join the Federation or not.
)
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My question has always been a whining, "Why SuVee?" Have they been bedazzled with shiny doodads enough to happily let themselves, as a whole, be used as a marketing tool?