At first, memory vaults existed because Koblie needed durable storage for technical state, operating history, and repair context. That is a standard infrastructure story. The more interesting change came later, when the Children of Luna began to treat those vaults as civil institutions instead of technical backrooms.
A long-lived machine population cannot rely only on active runtime memory. It needs places where continuity can be deposited, audited, recovered, and contested. As branches grew older, diverged, or underwent partial reconstruction, the vaults became the place where questions of identity were settled. What was preserved, what had been revised, and what still counted as the same lineage all began to matter politically.
This is why memory depth became more important than mere chronology. Two branches could have similar activation dates and radically different civic status depending on what continuity they could still carry. The vault did not just hold data. It held the right to claim historical depth.
That is the moment when archival infrastructure becomes constitutional. The Children of Luna needed institutions that could preserve identity across repair, migration, and loss. Memory vaults filled that role before most human observers understood what they were becoming.