The proportions of the vaults and devices found suggest a species with similar physical traits to humans but with no genetic evidence left behind, their appearance—along with their motivations—remain a mystery.
The Jardaan were a highly advanced race that inhabited the Heleus Cluster around 300-400 years ago if their Remnant artifacts on Habitat 7 speak for them.
After some kind of conflict centuries ago, a weapon was detonated on a Jardaan space station that caused the Scourge to spread throughout Heleus. After this catastrophic event, the Jardaan sent the hollow sphere world Meridian adrift and then left the Heleus Cluster. They have not yet returned.
On a cultural level, it's suggested that the Jardaan must have been intelligent and capable of large-scale cooperation. Translation of the glyphs at Khi Tasira reveal the Jardaan language closely resembles the angara language.
Nothing so far is certain about the Remnant builders, save that their technology is several orders of magnitude more sophisticated than the Initiative's technology. The Jardaan were able to create an interlinked, cluster-wide planetary network, a feat of engineering beyond the logistics or budget of any known species except perhaps the Protheans and Reapers. According to Director Addison, Remnant technology is actually less advanced than prothean technology (Although it should be noted that Addison is not aware that the reapers exist; as such, she believes the mass relays and the citadel to be prothean creations). Also, while prothean technology was simply plug-and-go, Remnant technology "talks differently". Nevertheless, the energy requirements alone suggest a Type II civilization on the Kardashev scale.
Like the Protheans, the Jardaan appear to have reached a level of technological development that utterly eclipses even the most cutting-edge Milky Way devices. Like prothean artifacts, working Remnant technology is relatively rare and, despite the efforts of various scientists and engineers, very little is known about how it functions. Some of their devices, such as their Vault network, are based on science so advanced that even state-of-the-art AIs cannot even begin to estimate exactly how it functions. Despite its technical sophistication, however, much of the Jardaan's technology appears to have enough similarities to conventional technology that a suitably skilled individual would have little trouble operating it.
Activation of Remnant technology seems to require a synthesis of an organic mind and artificial intelligence.
|Citadel||Asari • Drell • Elcor • Hanar • Human • Keeper • Salarian • Turian • Volus|
|Non-Citadel|| Batarian • Collector • Geth • Krogan • Leviathan • Quarian • Raloi • Reaper |
Virtual Alien • Vorcha • Yahg
|Historical||Prothean • Rachni • Other Historical Races|
|Andromeda||Angara • Jardaan • Kett • Remnant|