The Kohaku Cloud is an imposing nebula spanning hundreds to thousands of light years discovered in 889 ATGW at the very edge of the Outer Arm of the Milky Way Galaxy. Discovered by human explorer Ryoichi Kohaku, the Kohaku Cloud was his final adventure before his sudden disappearance.
Kohaku and his crew of six Eteno and humans discovered the cloud while searching for resource-rich worlds outside of the Milky Way. Grenger Mining Company had recently begun offering cash rewards for the discovery of new worlds free from any sentient influence. Desiring money for a better ship, Kohaku and his crew furiously combed the edge of the Outer Arm, discovering eighteen star systems, fifteen of which possessing worlds. At one point, a vast unknown mass filled up Kohaku's ship's sensor screen. Naturally, he set a course straight for this curious object. What he discovered was one of the largest nebulae ever observed. He eagerly ventured into the cloud, despite the many warnings given by his ship's computer. The final transmission from Kohaku and his explorers was heard fifteen seconds after entering the nebula, before all contact was lost. Six Imperial Navy corvettes and a destroyer conducted a limited search for the scout craft, and despite exercising the greatest caution, lost six fighters and the corvette ENS Hetzer. The disappearances are officially attributed to a mix of extremely-low visibility, massive random radio interference from three to four pulsars lurking relatively close-by in the cloud, and random, superdense asteroid patches. An observation station has been established just outside of the cloud, from which scientists launch satellites into the cloud, and on very rare occasions, crewed exploration ships. These ships are connected by carbon tether directly to the station.
If the Kohaku Cloud was a person, mothers would use it to scare children above all other monsters or spirits. When one approaches the nebula, they see an extremely dark wall of unsettling gas punctuated by the occasional flash of light produced by the 'space lightning' inside the cloud. On entry, visibility is exponentially reduced to the point where a potentially-dangerous object like an asteroid would be visible a mere few metres away from impact. In fact, it is these asteroids that add to the eerie atmosphere of the cloud. Random, ultradense pockets of asteroids are scattered across all parts of the nebula. These asteroids curiously resemble roughly-carved stone knives. Radio communication is difficult to employ in the Kohaku Cloud, as at least three pulsars are confirmed to lurk inside the slightly-explored sections of the cloud. Some estimated put the number as high as thirty. As of now, four planets are confirmed to exist in the nebula. These are named Omprat, Haruto, Walther, and Jamie, after some of Kohaku's fellow explorer crewmen who disappeared along with him. All of these worlds barring Omprat has an atmosphere composed of the cloud's own gasses.
- Haruto is a frozen world orbiting a black dwarf, whose surface temperature hovers only a few degrees above absolute zero. However, scans have revealed a molten core, and interestingly, strong evidence of life. A small handful of radio transmissions have been detected in the core, suggesting that there may be life in the core of Haruto that communicates via radio waves.
- Walther is easily the most recognizable world due to the peculiar gaping hole leading into the warm core. Multiple deep holes are scattered across the surface, but only one leads all the way to the centre of the planet. It is believed that the shafts are artificial, and because of them, the core has cooled down to about 120 degrees Fahrenheit. There is also evidence of former life in the core. It has been suggested that this and the hole leading to the core are related.
- Jamie, while not yet approached directly by a vessel, has been determined to be an ice-coated world. Nothing else is known about the planet.
- Omprat is the last discovered world in the Kohaku Cloud, near the edge. For reasons currently unknown, Omprat has an atmosphere consisting of mostly nitrogen and oxygen, despite the fact that very little of either gas resides in the cloud in proportion to other gasses. In 1,008, a research station was established on the surface. A network of satellites connected by tether marks the only confirmed safe passageway into the Kohaku Cloud, and is anchored by a supply depot sitting stationary around Omprat, and the observation station outside of the cloud. Omprat is shockingly fertile, and Maliskian crops introduced to the soil have done extremely well. While no extensive scans have yet been run, there is evidence of life at the core similar to Haruto and Walther.
Planets, asteroids, and burnt-out stars are not the only occupants of the nebula, however. A robotic research vessel venturing almost an AU from Omprat (farther than any other vessel, manned or otherwise, had strayed from their base at Omprat and returned) came across a peculiar object inside a loose collection of asteroids. Two vessels investigated the structure two days later, and discovered something amazing. The object was some sort of artificial construct. Made of a mix of deceased biological matter, asteroid, and clearly-refined metal, it seemed to have once been home to alien creatures, and most startlingly, a shipyard. Dozens of robotic scout vessels convened on the structure, then searched the surrounding five square AU. One came across a similar structure, made almost entirely of living organic matter. Contact was promptly lost with the scout, and when several other scouts investigated the location, nothing was found. These scouts subsequently disappeared.
Many other stellar objects are believed to possibly reside in the cloud, such as black holes or stars. One such object, a wormhole, has been discovered inside the cloud, half an AU away from Jamie. In 2626 ATGW, explorer Matthias Zhevhyit discovered the Zhevhyit Cloud, a small nebula about half an AU across near the star system 66 Kklxin, where notably the planet Rew is located. Scans revealed that the makeup of the cloud was identical to that of the Kohaku Cloud. Shortly after venturing in, he discovered a wormhole. He charged in, and exited in an uncharted section of the Kohaku Cloud. After seventeen seconds, he fled back through the wormhole. Organic matter similar to what was found in the constructs near Omprat was detected close to the Kohaku side of the wormhole. Immediately, explorers mapped out the entire Zhevhyit Cloud, and a research station was established at the Zhevhyit side of the wormhole. The wormhole has been determined to be quite young, and some have conjectured that it is artificial, noting its stability and the presence of organic matter around the Kohaku side.