Prothean Beacon

Prothean Beacons were ancient pieces of Prothean technology, built as a system of near-instantaneous communication across that vanished empire's galaxy-wide reach. Exceptionally rare survivors of the millennia since the Protheans disappeared, they transmitted their messages directly into a recipient's mind. The discovery of one on Eden Prime drew the SSV Normandy SR-1 to recover it and gave Commander Shepard the first warning of the returning Reapers.

Function#

The beacons formed a network of near-instantaneous communication that spanned the Protheans' galaxy-wide empire. Rather than conveying sound or images, they were built to interface directly with a person's brain, imprinting information mind to mind. Because so little Prothean "paleo-technology" had survived intact across the intervening millennia, a working beacon was a discovery of immense scientific value. When one was found on Eden Prime, word of it sent a shock through the Systems Alliance's scientific community, and the Normandy was immediately dispatched to recover it.

The warning on Eden Prime#

The message carried by the Eden Prime beacon was a warning about the Reapers, sent by the Prothean researchers on Ilos in a desperate attempt to reach any survivors and give them a message of hope. It was coded so that only Prothean minds could understand it, a precaution meant to keep any lingering Reaper from learning that Ilos had endured. At the time, however, the Protheans did not fully grasp the process of indoctrination, and so failed to anticipate that an organic servant of the machines might also receive and eventually comprehend the message.

That precaution, combined with the damage the Eden Prime beacon had reportedly suffered in Sovereign's attack on the colony, meant Shepard received the warning as a series of random, vivid images rather than a coherent transmission. The beacon responded without warning when approached, and the contact left Shepard unconscious for some fifteen hours and troubled afterward by recurring nightmares. Comprehending the message as it had been intended required the Cipher, a Prothean frame of reference that allowed both Shepard and Saren Arterius to make sense of its archetypes and imagery.

The beacon itself did not survive. It exploded after being used, and it has been suggested that the strain of transmitting its vision to Saren and then to Shepard in quick succession caused a system overload. Liara T'Soni, noting how exhausting she found it to touch Shepard's mind, observed that humans instinctively resisted the joining process, and suggested the overload may have come from Shepard reflexively fighting the vision rather than welcoming it as Saren had.

Other beacons and relics#

A second beacon, intact and fitted with an interface for accessing it, was found in Saren's laboratory on Virmire. Because it was undamaged, Shepard coped far more easily when its vision was transmitted. Whether Saren had discovered it on Virmire or brought it there from elsewhere was never made clear, and the beacon was presumably destroyed along with his base in the nuclear blast that leveled the facility. A Prothean video terminal on the planet Joab served a similar function, its vision partly identical to the warning about Sovereign and the Reapers, though it closed on an image of a pair of Collectors rather than a Reaper.

A further Prothean relic lay hidden on Thessia, the asari homeworld and the source of that people's advanced culture. During the Reaper invasion Shepard discovered and activated it, releasing a Prothean virtual intelligence known as Vendetta. Its data suggested that the recurring patterns of galactic evolution were not caused by the Reapers at all, and that the Reapers were merely servants of that deeper pattern, but before it could yield the last details Shepard sought, the agent Kai Leng appeared and stole the information away.