New Engineer information:
The ruins of their massive necropoli and pyramidal structures are spread across the stars. The sophistication of their fossilized biotechnology mystifies explorers while their megalithic stone statues and busts bear testament to their artistic and architectural superiority.
Terminology:
Hieroglyphic tablets unearthed on Tanaka 5 call them Ossians. The decoded Derelict beacon on LV-426 made reference to the Mala'kak. Whatever they call themselves, to modern humanity Praetomorph they are known simply as the Engineers.
The Prometheus' fate:
The star configuration Dr. Elizabeth Shaw and Dr. Charles Holloway discovered turned out to be a star map which led the Prometheus mission to a distant moon and the ruins of an Engineer outpost. Whatever they found was erased from the archives, the destination of was classified and all but forgotten, but stray transmissions picked up by company satellites confirmed the existence of the beings.
Over the decades, covert corporate scientists have made attempts to classify them. The number of them with religious leanings often liken them to the Nephilim, fallen angels cast out of heaven for meddling with- or in this case creating- humanity. As the first remains of their kind were discovered at the helms of their dead ships, some have labelled them Mundus gubernavi, or '"universal pilot" like the misnomer Internecivus Raptus, or "murderous thief" that is sometimes associated with Xenomorph XX121, the classification, in of itself is incorrect. There is no "pilot" genus to draw upon.
The late Doctor Shaw's scientific notes that were recovered in a garbled signal sent after the loss of the Prometheus provide the most shocking revelation about the Engineers, their DNA is human. They predate us, they are us and we come from them. The rediscovery of Doctor Shaw's notes has led to a more scientific name for the giants, Homo Genitor, meaning creator of man.
Not much else is known about them, what else is known is being gleaned from a number of extrasolar archeological dig sites discovered within the last three years as the Frontier has advanced into the unknown. No living Engineers are known to exist and the xenoanthropologists aware of them believe they died out thousands of years ago. Their passing is marked by their abandoned citadels, derelict ships and their biogenetic and evolutionary experiments. What is also clear from Doctor Shaw's transmissions is that even though they created humanity, at a certain point a millennia ago they decided to undo their creation, attempting to wipe out the Earth and start again.
Physical form:
The Engineers, while a number of fossilized discoveries place them at 4.5 meters tall, most agree that they averaged around 2.7 meters tall. Theories suggest unique castes of Engineer exist with physical alternatives developed into them, thereby distinguishing civilian and military factions. Others postulated that not all the crumbling edifices unearthed belong to the Engineers but other species seeded by or predating them. If that is the case, the civilisations responsible also, no longer exist. And pointing to the enormous remains of the so-called "Space Jockey" specimen reported witnessed by three parties. A number of xenoanthropologists suggest the Engineers based their biomechanical technology on creatures greater than themselves- strange beings of immense size replete with pachydermic probosci.
However since the specimen in question was unfortunately destroyed, all of this is merely conjecture.