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 created by Cort as a weapon of war between Conkram and Sol. As the armies of both sides heavily depended on Seru, it was created as a way to amplify the strength of Conkram's Seru, effectively nullifying any Seru-granted advantages Sol had. Though it was deemed a handy solution to the war, the Mist backfired on Conkram in a public demonstration.
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 throughout the entire globe.
The Mist has the strange power to drive Seru and humans wearing Seru into mindless, bloodthirsty creatures with the single intent of killing or turning those that aren't Seru monstrosities into such. The Mist affects most Seru, save a select few called Ra-Seru. Creatures of the Mist thrive in it, and 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 a supply.
Mist itself is not harmful to humans, as any normal humans caught in the Mist are able to breathe in it without harm. The true danger of the Mist lies in what it does to Seru. Seru go berserk in the presence of the Mist, and will control their human host's actions. Seru in the Mist that are not occupying a human tend to attack 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.
It is worth noting that although Mist does not affect humans it is poisonous to Genesis Trees. Genesis Trees caught in the Mist will slowly die over time, with thicker concentrations of Mist able to kill them more quickly. Although Ra-Seru have a natural resistance to the Mist and will not turn crazed like normal Seru, thick enough concentrations of Mist will make them ill and weaken them. The only way for a Ra-Seru to overcome this weakness is through gaining power by reviving a Genesis Tree.
Mist is spread by Mist Generators, and moved by common wind. The town Vidna uses large, powerful windmills surrounding the town to repel the Mist. It's also notable that Mist is heavier than air, meaning that humans at high enough elevation are safe from it.
Mist can be driven from nearby areas by the revival of Genesis Trees. An even more powerful method of driving Mist away is by the destruction of the Mist Generators in the area. There are four Mist Generators in Legaia; one in Drake Kingdom, one in Sebucus Islands, and two in Karisto Kingdom.