The Krawl are a alien race or group of alien races with a goal of devouring the universe. Whenever they appear in battle they come out of a "black" vortex. The vortex changes color depending on the property of the krawl that it contains. They come in groups of at three in Spectrobes, up to 3 waves of two to four in Spectrobes: Beyond the Portals, and groups of varying size in Spectrobes: Origins.
Each Krawl posesses a elemental property, like the spectrobes. In Spectrobes and Spectrobes: Beyond the Portals the properties are Corona, Aurora and Flash, with Corona strong against Aurora, Aurora strong aganst Flash, and Flash strong aganist Corona. A fourth property, Dark, also exists, being neutral to all other properties, and only used by Maja and the Xelles she/it teams up with.
In Spectrobes: Origins the properties goes as follows: Fire, Plant, Earth, Sky, and Water. In order to have an advantage over he Krawl you need the oppisite property that they hold. In this case fire beats plant, plant beats earth, earth beats sky, sky beats water, and water beats fire. A sixth property, Clear, also exists, and it is neutral to all other properties.
Prior to all games
The Krawl fought the Spectrobe Masters in the Great Krawl War in the Kaio system, and are defeated, but the Spectrobe Masters are killed and their Spectrobes convet to fossil form and are scattered throughout the universe. The Krawl later attack the Fubuki, Kagero, Hakaba and Giorna systems successfully (the first three may be attacked some time between Spectrobes and Spectrobes: Beyond the Portals), attacked the Kaio system again, with little sucess, but they did cause such difficulty for Krux (a Specrobe Master) that he tried to use a mysterious black substance to fight the Krawl, but it turned out to be some of a Krawl and contaminated him, turning him into a human-Krawl hybrid that went on to rule them, and may also have attacked other, unknown, systems.
In Spectrobes the Krawl attacked the Nanario system, just as Adolus reached it after escaping the Giorna system to seek help. They first appear to the humans residing in Nanario on Diachi, just after the main character of the game, Ralllen, arrives to investigate the pod Adolus arrived in, and are defeated by Rallen and two Spectrobes that Rallen acquired and commanded by accident just before the battle.
The Krawl are then found across the Nanario system, and their base is eventually found on the planet Medio, but it is inaccessable due to the numbers of Krawl on the planet's surface. An area of the planet is cleared of Krawl by using the planet Hirmuno (acually a giant lens made by the ancients to focus sunlight on Medio to keep Krawl away) to iluminate the planet with strong light, which repels the majority of the Krawl. Deep inside the planet, Rallen fights the huge Krawl called Gorblada, which appears to be the Krawl's leader, and defeats it, which repels the Krawl.
Spectrobes: Beyond the Portals
In Spectrobes: Beyond the Portals the Krawl attacked the Nanario system again, led by Krux and the High Krawl - Jado, Gelberus, Gronos and Maja. The Krawl open portals to the Fubuki and Kagero systems to lead invasions of more Krawl from each system, then a portal to the Hakaba system is opened by the humans in order to find Adolus, who vanished during the Krawl's earlier attacks.
Once Adolus is rescued, the humans discover a planet in the system that is protected by a dark forcfield that makes it impossible to touch the planet or see it. Once the Dynalithium is found, it is used on the forcefield to break it, and the humans attack the planet, which is the Krawl's base. It contains Dark Spectrobes, which are formed from the fossils of ordinary Spectrobes under a Dark Lake when the Dark Lake is formed, and may serve the Krawl, Krux and beings Krux calls True Dark Spectrobes, along with a Krawlosphere. When Krux is defeated, the Krawl are repelled again.
In Spectrobes: Origins, the Krawl attack the Kaio system with the Krawlosphere seen in Spectrobes: Beyond the Portals.