Dagon Dagon is a demon lord , also called Prince of the Depths . His realm is the 89th layer of the Abyss , and is known as Shadowsea . Dagon is an obyrith . Dagon is first mentioned in the first edition " Dungeons & Dragons " sourcebook " Monster Manual II " , where it is said in passing that he rules a liquid layer dominated by marine dretch es , hezrou s , kraken s , and horrible fish - monsters . Description . Dagon ' s form is a mixture of both octopus and fish . History . Dagon ' s history in the Realms lies below the surface of the Sea of Fallen Stars and the waters in the west of Maztica . He and his minions lurked for a long time in the Trench of Lopok and were only known as " Those Who sleep Below " . They infested the dreams of those who swam in the Sea of Fallen Stars with nightmares . The most ambitious of the demons was Prince Dagon , who planned to overcome a pantheon of sea creatures and achieve their divine powers . To reach this goal he brought the depths of the Sea of Fallen Stars under the control of his servants and their forces . The next step was made with long forgotten eldritch magic . He restricted the influence of the deities of the Shalarin in the Sea of Corynactis , on the West of Maztica . The next step was the creation of five " wild tides " to sweep large numbers of sharlarin into the Sea of Fallen Stars , where his minions could slaughter them . The first wild tide began in - 1509 DR with opening of the Wildtide Portals connecting the two ocean realms . Many Shalarin were swept into the Sea of Fallen Stars where roughly 70 % died under the attacks of Dagon ' s servants . The rest was only rescued by the intervention of enemies of Dagon , like merfolk . Dagon repeated this tactic every 720 years and the last wild tide was in 1371 DR . This time the portal stayed and became permanent . The shalarin of Faerûn kept the portal a secret , fearing that others could use it for their own ends . But another fact was more disturbing for them . Between the fourth and fifth tide , the shalarin of their homelands near Maztica , all but abandoned their gods because they had grown silent . Instead of the gods they began to venerate the demon Dagon and his cult became the dominant religion in the Sea of Corynactis . The shalarin of the Sea of Fallen Stars cut of the travel between their communities . But it was too late and the cult of Dagon has already taken root among their ranks and grows in secret . Dagon also seems to have heroic , " good " progeny in Faerûn , one for certain in the form of Captain Thoster , one of the heroes attempting to stop the eladrin Malyanna from opening the Far Manifold with the Key of Stars . Captain Thoster is a " merchant " ( pirate ) with a witty , macabre sense of humor and a loyal friend . Thoster ' s heritage manifests itself in increments periodically during this quest ; originally he believes it to be of Kuo - Toa origin . Eventually it is revealed to him ( in an extremely painful transformation ) that he is in actuality a Demon Scion , a direct descendent of Dagon . Cult of Dagon . Dagon is served by aquatic demon s , especially wastrilith , and is worshipped by aquatic races such as kraken , chuul s , sea hag s , water naga s , and kuo - toa . The Outcast Dagon . The demon lord Dagon should not be confused with the exiled devil of the same name , who dwells on Avernus , first layer of Baator . Originally known as Jaqon , Asmodeus forcibly changed Jaqon ' s name to Dagon to thwart attempts to summon the offender . Appendix . Notes . Outside of the Forgotten Realms universe , the demon lord Dagon refers to a horror short story written by , where Dagon is similarly described as a monstrous sea - deity . External Links . is originally a Semitic fertility god . " Dagan / Dagon on ORACC " " and WiBiLex ( German ) "