In Destiny 1 rise of Iron, the final boss of the raid was named Aksis Archon Prime. An Archon is a religious figure in a Fallen house that takes care of the house's Prime servitor, and as expected Aksis was previously an Archon before being changed by Siva. But here's the thing, Prime servitors dispense ether for the Fallen house's... But the Devil splicers don't need ether, instead they just need Siva. I think that after we killed Sepiks perfected, Aksis took on the title of Prime because he was the last thing providing Siva to the splicers. Thus becoming both an Archon and a metaphorical Prime servitor. I'm probably incredibly late on this but hey what the hell