The Na'arbi were a species claiming to be one of the oldest races in the known universe, with some claiming to exist in the universe before our current universe. As of 2364, they were reported to be nearly extinct.
The Na'arbi, in their native form, appear as short, white- or grey-skinned aliens with wide, black, almond-shaped eyes. They have telepathic and telekinetic powers beyond any race encountered by the Federation to date. They are immortal due to a supposed "Fountain of Youth" they and their enemies, the M'Tar, perfected.
The Na'arbi integrated themselves into normal society, disguising themselves as a native or familiar species. Hahn Jun-Seok disguised himself as a human. (Star Trek: The Prospect Chronicles: "Lady Lazarus")
Legend (purported history)
Captain Hahn speculated that according to M'Tar and Na'arbi legend, the two races were created as different ends of the spectrum and would battle until the end of eternity, and that if that legend was true, the M'Tar could have existed in an universe prior to the Big Bang. The war between the M'Tar and Na'arbi was called The Great War.
Another legend also claimed that the reason for the Big Bang was an intergalactic war between the M'Tar and the Na'arbi, one which destroyed the majority of both sides' populations and both races' home galaxy. The legend stated that the surviving M'Tar created a weapon of such mass destruction, it caused instability in the expansion of the universe, and once fired, the weapon contracted their universe at an amazing rate. This contraction and then sudden expansion created the Big Bang, and the M'Tar, as well as the Na'arbi, survivors supposedly hid in a "pocket" of space not affected by the explosion.
Upon arrival, the Prospect crew discovered the remnants of the USS Artemis. An away team, consisting of Commander Anne Lansing, chief of security George Stratos, counselor Daniel Radke and three security officers beam over to the wreckage (after environmental controls were brought back on-line) to search for bodies. They split up into three groups: Stratos and his escort on the bridge; Lansing and her escort in engineering; and Radke and Ensign Garrett in the front section of primary hull (which was blown out into a wide, three-deck or higher area contained by a force-field).
Lansing and her escort discovered the warp core was not overloading at the time the survivors abandoned ship, but something or someone deliberately sounded the warning when no real threat existed. They bring the warp core back on-line.
All reported finding no bodies aboard the ship, even though so many of their colleagues had died that day.
The other teams converged on the area to find the Liaison and Link bound to the Artemis's frame by some sort of biological vine (tied into the Link's back, which, in turn, was wrapped around the Liaison's body). The M'Tar revealed they originally wanted to use the Artemis to infiltrate the Federation while the conspiracy aliens attempted to take control of Starfleet. Unfortunately, they were left to drift for years (as their plan failed), but their new plan involved taking control of the Prospect and returning to enslave the Federation.
Unbeknownst to the M'Tar, their control on Radke weakened when they left his body to feed on corpses (the latest being one of the Prospect security officers). Undercover Na'arbi agent Hahn Jun-Seok, revealing some of his true identity to Greene on the Prospect, transported over to the Artemis, exploiting this weakness. After setting the warp core to critical, Hahn enabled the Prospect to beam over Lansing and her away team, sans the transformed Greene and Garrett.
The Prospect pulled away as flashing emanated from the hull breach in the Artemis's primary hull. At the last moment, Hahn broke Radke and Garrett away from the M'Tar vine and transported them back to the Prospect before the Artemis exploded, sucking the debris, Hahn and the two M'Tar through the portal the M'Tar created into the M'Tar Domain. The portal collapsed with the explosion. (Star Trek: The Prospect Chronicles: "Lady Lazarus")
Attitude towards other races
Unlike the M'Tar, the Na'arbi supposedly felt other races and beings should not be involved in the cross-fire of their war. Keeping in touch with this idea, the Na'arbi rarely encouraged other races to fight the M'Tar unless absolutely necessary.
The Na'arbi and Starfleet Command might be working together as, in 2372, Na'arbi agent Hahn Jun-Seok destroyed all known prototypes, records and research on the folded space drive from Dr. Samantha Delaney's base at Dante Station. (Star Trek: The Cantabrian Expeditions: "An Innocent Time")