The Koros-Strohna, referred to as worldships within the Galactic Basic Standard, were colossal spacecraft. These vessels served as homes for entire communities belonging to the extra-galactic Yuuzhan Vong, supplying them with sustenance and sanctuary. Furthermore, these worldships acted as operational centers for more intense battles or confrontations. The Yuuzhan Vong's culture and faith system expressed a profound disdain for anything resembling "modern" technology, including items like droids, sophisticated computer networks, electronic devices, or nuclear energy (among other concepts). Consequently, their worldships were invariably constructed using organic components. Numerous ships were either built from, or received their power from, living organisms, such as yorik coral or other living invertebrates.
Functionally, a worldship mirrored the role of the resurrected Emperor Palpatine's Eclipse-class Super Star Destroyers, serving as a multifaceted entity. It was a community, a warship, a psychological weapon, and a mode of transportation, all consolidated into a single unit.
The Koros-Strohna, like all other Yuuzhan Vong technological creations and ships, was constructed from yorik coral. This coral then developed symbiotic relationships with various other organic substances and organisms employed in the ship's construction, providing it with defensive capabilities, propulsion, and weaponry. Maw luur acted as a recycling mechanism, as well as offering essential life-support functions for the ship. A worldship shared more characteristics with a living planet than a conventional spaceship, and, akin to the majority of Yuuzhan Vong bioengineered vessels, it did not resemble a spaceship in any way. The primary portion of the ship consisted of a disc-shaped mass, densely covered with numerous projectile defense systems, along with other protrusions. Extending from the central edges of the worldship were several expansive, spiraling "arms", giving the ship a resemblance to a spiral galaxy or a hurricane. In regions with minimal gravitational pull, such as the vast spaces between galaxies, the Koros-Strohna had the ability to extend numerous membraneous "tendrils" known as outrider ganglia. Each membrane was secured by hundreds of coralskippers, or yorik-et, which were smaller, similarly coral-based "starfighters" used to assist in unfolding the membrane. Once fully extended, the ganglia functioned as cosmic sails.
Dovin basals propelled the worldship by generating gravity wells that pulled Yuuzhan Vong vessels across the interstellar void. When these organisms focused their energy wells, they had the capacity to collapse space stations, entire planets, or moons, even forcing a binary system into collision. Dovin basals were also capable of stripping enemy ships of their deflector shields. The worldship's own defensive measures also depended on the dovin basals' ability to manipulate gravitational wells to intercept incoming enemy fire or other potential attacks. To conserve energy, worldships could produce artificial gravity through rotation, thereby preserving the dovin basals.
Worldships were defended by hundreds of yaret-kor installations that ejected molten "slag", or magma, at opposing ships. These ranged in size from cannons comparable to starfighters to turbo laser-sized weapons similar to those used by the New Republic. These magma-based weapons varied from small openings with the potential of blaster cannons to larger emitters capable of launching massive volcanic boulders, up to the size of a small starship, over considerable distances. The Koros-Strohna's armaments were positioned irregularly and recharged gradually as new magma was produced; these weapons demonstrated remarkable accuracy, despite their unusual nature.
Another weapon was an enormous, tubular worm known as the dread weapon, which extended from the depths of the worldship. The dread weapon could be deployed to gather nutrients, ensuring the worldship's survival. The Gorros' Fen served a similar purpose.
Further defensive capabilities were provided by the worldship's cargo and troop bays, which could carry over 5,000 warriors, along with coralskippers and terrestrial ground vehicles. Given the vessel's immense size, the Koros-Strohna often accommodated a small Yuuzhan Vong military force.
A Yuuzhan Vong worldship could live and function for a minimum of 500 years, possibly longer, with some known to operate for up to 1,000 years, as demonstrated by the Baanu Miir. As a worldship approached the end of its lifespan, its dovin basals would exhibit color variations, and myogens would proliferate within its corridors.
In 26 ABY, the worldship Baanu Miir housed twelve thousand Yuuzhan Vong and was almost 1000 years old (an age considered ancient), was dying and no longer capable of traveling at faster-than-light speeds. It remains uncertain whether these figures were typical for worldships. The Baanu Rass, one of the most massive worldships, measured 120 kilometers across, nearly the size of the original Death Star. During the journey through the intergalactic void between galaxies, specific drugs were introduced into the worldship's environment, instilling its occupants with a sense of purpose and unity to prevent mental breakdowns resulting from the pressures of a prolonged voyage across space to their Promised Land.
The Alak Schou was among the worldships used to transport the invasion force into the galaxy. The Domain Hul worldship acted as a staging area for the Yuuzhan Vong offensive against the New Republic during the assault on Borleias.