According to the books left by Kain, the support-type Magic Array that creates the black mist was researched by Kain himself.
The main function is to make those who enter lose their five senses and become disoriented, causing them to endlessly circle around.
Either they circle until they perish or get dealt with effortlessly by Kain, unable to even touch the defensive barrier created by the Defense Magic Array inside.
The landscape and climate of the Chaotic Sea Domain vary greatly, so the support-type Magic Array researched by Kain, which creates the black mist, actually blends well here rather than standing out.
The most important thing is that this Magic Array was researched by Kain alone, so others cannot possibly understand it.
Without understanding, it would be mistaken for a peculiar geographical climate rather than being recognized as a Magic Array at a glance.
