Idk if this counts as spoilers but if Adri is essentially like a computer virus where did he get a physical body from?? Did he steal it from someone or was it provided for him to he put into??? So much to think about........
GREAT QUESTION! He stole it :)
He stole the body and the body's name for himself, and then fabricated an appearance and personality and mannerisms.
His body is one of the previously many nanomachine systems set in place in the Old World to safeguard and maintain both people and machinery. They were known as Guardian Arrays, but now they are referred to as Angels. Only two are currently known to still be fully operational, Adri being one of them.
The Fall (Otherwise known as the literal end of the world) was an apocalypse event where a system bug caused every advanced enough AI to go rogue and turn on mankind. It started small, but spread far and wide exponentially and it irreparably changed whatever it infected. The Arrays, being as important as they were, had more safeguards in place against this stuff but it still didn't stop them from becoming infected. Especially ADRIEL. The corruption inside it became severe enough that it first became a virus, and then grew into a full fledged self compiled AI that was notorious enough to be given its own name "Usurper", though you know it as "The Hydra".
The only way to avoid being completely wiped out during this event was to mass purge absolutely EVERYTHING (so humanity lost basically 99% of their tech and their knowledge). Did this work? kiiiind of.
Because of it's self compiled nature, ADRIEL was never able to be properly purged, so instead it was (after a monumental, worldwide effort) put to sleep beneath the earth, never to be disturbed again.
Until....