The Mist (霧, Kiri) is the central source of conflict in Legend of Legaia. It is created out of several Mist Generators that spread the substance throughout Legaia for the purpose of turning Seru malevolent and transforming the humans who wear them into bloodthirsty monsters.
Mist was first introduced to Legaia by Conkram's prince, Cort, as a weapon of war to be used by Conkram against their nemesis Sol. In his research, Cort and the court scientist, Jette, discovered a method of opening a gateway between Legaia and the realm of the Seru, called Seru-kai, where abundant Mist was discovered in its atmosphere. While wearing Seru within the Seru-kai, they discovered that the strength of their Seru had been heavily amplified, and as such deemed it the solution to crushing their rival Sol and bringing victory in the war between them. In order to approve its use in battle, Conkram's king, Nebular, required that a public demonstration first prove successful.
When a volunteer wearing a Seru was put into the chamber containing the Mist, his strength was amplified as a result of the Seru going berserk. The volunteer shattered the chamber, spreading Mist throughout the nation. Although the outbreak was stopped by three unknown heroes, Cort and the Four Wise Men of Conkram conspired together and unleashed the Mist once again, spreading it throughout the entire globe.
Mist is native to the atmosphere of a location on the border of Seru-kai called Rogue's Tower. It is the breath of an evil Ra-Seru called Rogue who rebelled against Tieg and the other Ra-Seru 1,000 years ago before being sealed inside the tower as punishment for its betrayal. The Mist contains Rogue's malevolent will, and due to Rogue's insatiable desire to take over the human world, any Seru caught in the Mist is taken over by Rogue's malice and will attack or possess any human in sight.
Although Ra-Seru are able to resist the Mist's effects, a high enough concentration of it will weaken a Ra-Seru and cause it to go berserk just like the standard Seru that wander the Mist. Certain types of Seru even feed on the Mist to grow. Though Seru do not need Mist to survive normally, Seru driven mad by the Mist can die when suddenly cut off from it. Mist itself is not harmful to humans, as any normal humans caught in the Mist are able to breathe in it without harm. However, the presence of Mist has been shown to cause humans uneasiness and feelings of sadness to sweep over them.
Humans possessed by Seru in the Mist become slaves to their will and turn into monsters. When a Seru possesses a human it also merges with it. If the Seru's body is forcibly removed from its human host while in the Mist, the human will die. It is noted that the bodies of humans when possessed by Seru do not age, meaning they can live eternally, as well as not require sustenance of any kind, although the reasoning for this is unknown. The only true way to safely separate a Seru and a human in the Mist is to remove the Mist from the immediate area.
Although the reason isn't entirely clear, withered Genesis Trees caught in the Mist will slowly die over time, with thicker concentrations of Mist killing them more quickly. However, a Genesis Tree in full bloom radiates an energy that repels the Mist from its vicinity. An even more effective method of driving Mist away is by destroying the Mist Generator that creates the Mist in the first place. There are four Mist Generators in Legaia; one in Drake Kingdom, one in Sebucus Islands, and two in Karisto Kingdom.
Mist in Legaia is spread by Mist Generators and carried by the wind. Mist created by Mist Generators has similar physical properties to Mist created by natural weather, and being heavier than air, it is unable to reach humans that dwell in high enough elevations.