User blog comment:Supahbadmarine/Andromeda Xeno Lab/@comment-10514705-20110622191252/@comment-10514705-20110622202847

That's an interesting idea, without an equivalent to the War in Heaven the races of the Andromeda would most likely have no idea of the existence of the C'tan. So if the C'tan were more careful with their endeavours in Andromeda then I think you are correct that they would be aware of the galaxies inhabitants without the natives being aware of them.

I have another idea related to their origins though. Without a race like the Necrons in their Galaxy, the Andromeda native C'tan largely died out due to starvation. The 'fittest', so to speak, survived, producing the Oligarchi as a twisted form of offspring, capable of reproducing more readily. In the centuries leading up to the 41st Millenium the Oligarchi become more active in their attempts to bring about the recreation and reawakening of their ancestors, successfully causing several new C'tan to be formed by the sacrifices of their own species.