Koros-Strohna, known as worldships in Galactic Basic Standard, were immensely large, organically created spacefaring vessels that housed entire communities of the extra-galactic Yuuzhan Vong, providing them with food and shelter. They also served as a staging ground for long battles.
Similar in function to the reborn Emperor Palpatine's Eclipse-class Super Star Destroyers, a worldship was a transport, battleship and a psychological weapon all in one.
A Koros-Strohna amid the Yuuzhan Vong fleet
Like all other Yuuzhan Vong vehicles and vessels, the Koros-Strohna, or worldship, was made of yorik coral. The yorik coral also formed symbiotic relationships with countless other organic materials to provide weapons, propulsion systems and defensive capabilities. Maw luur served as a recycling system as well as provided valuable life support to the vessel. A worldship had more in common with a planet than a starship and, like most other Yuuzhan Vong bio-engineered vessels, did not appear to be a starship at all.
Its main body was a disc-shaped bulk littered with hundreds of weapon projections and other protrusions. On the edges of the worldship were several large spiral arms, causing the ship to resemble a galaxy. In areas where the gravitational pull was weak, including the region between galaxies, the Koros-Strohna extended membranous tendrils called outrider ganglia. Each tendril was anchored by hundreds of coralskippers, which helped unfold the membrane. Once unfurled, the ganglia served as cosmic sails.
Dovin basals propelled the worldship by projecting gravity wells to drag Yuuzhan Vong ships through the interstellar void. When these organisms concentrated their energy wells, they could cause a space station to collapse or force a moon to collide with its orbital partner. Dovin basals could also strip enemy vessels of their deflector shields. The worldship's own defenses also relied on the dovin basals' ability to use gravity wells to intercept incoming torpedoes and other weapons. To conserve power, worldships could generate artificial gravity by rotating, thus preserving the dovin basals.
They also made use of a membrane, called outrider ganglia, that acted as a solar sail when traveling through space.
The Domain Hul worldship at the Battle of Borleias
Worldships were protected by hundreds of yaret-kor emplacements that spat molten slag at enemy vessels. These ranged from starfighter-sized cannons to turbolaser-sized weapons similar to those used by the New Republic.
These magma weapons ranged from small openings, with the capability of blaster cannons, to large emitters, which could shoot flaming rocks the size of small starships over great distances. The Koros-Strohnas weapons were spaced sporadically and recharged slowly as new magma was produced, though they proved fantastically accurate despite their unconventional technology.
Another weapon was the huge, tubular worm called the dread weapon, which extended from the bowels of the worldship. The dread weapon could be used to gather nutrients for the worldship to stay alive. The Gorros' Fen served a similar function.
Additional defense came from the worldship's cargo and troop holds, which could transport more than 5,000 warriors along with coralskippers and planetary vehicles. Due to the vehicle's size, the Koros-Strohna could transport a small Yuuzhan Vong army.
A Yuuzhan Vong worldship lived for an average of 500 years or more. However, they could live up to twice that long, as the Baanu Miir proves. When a worldship started to near the end of its life, it would develop color variations on its dovin basals, and it would grow myogens in its corridors.
In 26 ABY, the worldship Baanu Miir held twelve thousand Yuuzhan Vong, and was nearly 1000 years old (an age considered ancient), dying and no longer able to travel faster than light. It is unknown if these figures were typical for worldships. The Baanu Rass, one of the largest worldships, was 120 kilometers across, almost the size of the first Death Star. During the trek through the intergalactic void between galaxies, certain drugs were circulated into the worldship's interior, which infused its inhabitants with a sense of purpose and belonging in order to prevent them suffering mental breakdowns resulting from the stresses of a long journey across space to the Promised Land.
The Alak Schou was one of the worldships used to transport the invasion force into the galaxy. The Domain Hul worldship served as a base for the Yuuzhan Vong assault against the New Republic during the attack on Borleias.
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