The Jardaan are a mysterious species or faction responsible for building the bots and technology known as the Remnant. According to recordings and findings from Khi Tasira, they were interested in not only wide-scale terraforming but the creation of sentient life. One of their successful creations, the angara, were seeded on multiple worlds in the Heleus Cluster. The Jardaan's motivations for this creation are still unknown.
Their work was disrupted by the deployment of the Scourge weapon, the result of either an external threat or a rift in Jardaan society. This weapon devastated the worlds that the Jardaan had cultivated and forced them to leave the Heleus Cluster, though not before disengaging Meridian and sending it to safety.
The present whereabouts and disposition of the Jardaan are not known. Whether they will return to Heleus remains to be seen.
An artificial creation must have a creator, but there is scant evidence of whomever created the Remnant. I have consulted the Nexus scientists, scans obtained by Peebee—on the condition that I not rearrange her data—and records of your own investigation, but my conclusions remain speculation.
We can be certain that the Remnant builders are several orders of sophistication above the Initiative's technology. Interlinked cluster-wide planetary engineering is beyond the logistics or budget of any known species. The energy requirements alone suggest a Type I civilization on the Kardeshev scale.
On a cultural level, the builders must have been intelligent and capable of large-scale cooperation. 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.