possible appearance of an Uka'ra from the ancient records
The Uka'ra were an ancient and long extinct spacefaring species that once existed from the Prothean Cycle, they were once allies of the Protheans and willingly joined their empire during the Metacon War for their vast intellect and fast adaptation.
Many of the Uka'ra researchers had discovered some unusual anomalies from the Relays only to discover too late when they were wiped out by the Reapers. Knowing it was futile to defeat them, but have learnt the about the repeating cycles of Reapers harvesting galactic civilisations and the connections to the Mass Relays they have become dependent on, finding a region that is inhabited by several potential races who could escape the same fate as their species and destroyed many of the relays, leaving behind a warning about them.
They have assisted the Protheans to secure the blueprints of the Crucible in secured areas for the next cycle to prevent any indoctrinated forces from gaining access to the files. By the end of the war, it is likely many of the Uka'ra have perished by the Reapers.
50,000 years later, the remains of their civilisation have been on their homeworld Firok where their technology would be discovered by the Galjen and possibly the growing faction known as Providence.