Creatures of the deep blue

Every child of the Dark Side grew up listening to the same story about the All-reaching sea monsters. Those mysterious creatures would lurk in the deep waters and snatch those who dared to explore the coast further than the shallow waters. Mindresses (a common name for all the women who take care of the youngsters during their education and adolescence) would tell stories of the All-reaching - sea monsters with countless tentacles. 
Being pulled into the depths and drowned was not the worst fate for those who dared disturb the peace of these hostile monsters. Mindresses tell tales of people returning from such encounters forever changed, insane and completely dysfunctional. The terror they were inoculated with would never left them. Such people would speak in tongues, peel their own skin, eat rocks and driftwood and eventually die.
Another type of these stories is about a mind-altering effect that isn't as lethal - at least for those who keep their distance from the people affected. It is said that swimming in the ocean during the periods of Great Glow, when the ocean looks like a living patchwork of radiant green and blue segments, will make one mad with murderous rage. Those who are affected become extremely violent and remain in this state of mind for a couple of hours. After the effect wears off they have no recollection of it and collapse in fatigue. 
Although no one is daring enough to try their luck with these myths, most people wave off these myths as scary stories to keep the children in line. Even so, the Darksiders are very reluctant about leaving the shallow waters of the coast. Many astronomers have reported sights of eight-tentacled shadows in the depth. Since these observations are usually made from the heights of the Karai observatory, they have been disregarded as cloud shadows and fish swarms.