Canon:Dagon

In the Dungeons & Dragons fantasy roleplaying game, Dagon is a obyrith demon lord, also called Prince of the Darkened Depths. His realm is the 89th layer of the Abyss, and is known as Shadowsea. As one of the oldest demon lords in existence, Dagon is said to possess vast and forbidden knowledge.

Publishing history
Dagon is first mentioned in the first edition Advanced Dungeons & Dragons sourcebook Monster Manual II, where it is said in passing that he rules a liquid layer dominated by marine dretch, hezrou, kraken, and horrible fishmonsters.

Dagon is fully described years later, in the game's third edition in Fiendish Codex I: Hordes of the Abyss. Dagon's realm is described on Wizards of the Coast's website.

Dagon appeared in the fourth edition Monster Manual 2 (2009).

Description
Dagon appears as a colossalsized eel with the leering fanged face of a deepunderwater fish. Numerous suckered tentacles cover his body, two of which ends in fingerlike digits tipped with long sharp talons. Dagon's symbol is six spiraling tentacles arranged around a fanged mouth, and his favored weapon is the harpoon.

Relationships
Dagon and Demogorgon have an alliance of sorts, and it is rumored that Demogorgon gained his power and influence from the unspeakable knowledge he has gleaned from the Lord of the Depths.

Other than his alliance with Demogorgon, Dagon has few allies, and fewer enemies, for most other demon lords prefer to leave Dagon alone in his deep realm; those who do not are now dead. Despite being an isolationist, many demons, lords or otherwise, pay tribute to Dagon in the hopes of gaining information about the Abyss from him, as he is also revered throughout the Abyss as a great sage and oracle. The demon lord Lascer has attempted to ally himself with Dagon at the urging of his master, Oboxob.

Though Dagon has followers among the kuo toa, the feelings of their patron goddess, Blibdoolpoolp, are unknown on this matter.

Realm
Dagon's realm, known as Shadowsea, is the 89th layer of the Abyss. Shadowsea is an underwater realm with a seabed dotted with ruined cities, but without a surface. At certain points, if one ascends or swims upward, he will find himself surfacing on the 88th layer, which is the Gaping Maw of Demogorgon.

Worshippers
Dagon is served by aquatic demons, especially wastriliths and the obyrith uzollrus. He is worshipped by aquatic races such as kraken, chuul, sea hags, water nagas, and kuo toa.

History
Dagon is one of the few obyrith lords that are still in power in the Abyss, mainly from his isolationist nature and his sheer power. The hostile nature of his realm also protects him from any invasion attempts by rivals. When the Queen of Chaos tried to rally the obyriths in the war against Law, Dagon was one of those who refused her call, and one of the few who escaped her resultant wrath, mostly because the Queen feared his power. After the fall of the obyriths, Dagon remained as he always was, safe and secure in his deep realm.

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. The original, in turn, took this as a grave insult.

Forgotten Realms
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 shalarin 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.