The northern ocean was once the site of numerous conflicts among the seven great Houses formed by the Akerys, the Walshs, the Deminicis, the Dyonistos, the Rohans, the Blonays, and the Castellans. Yet, in the face of rising waters that threatened to engulf their lands, the sovereign of Dyonistos forged the alliance that united the seven Houses in the construction of their underwater habitats. The location of each kingdom was carefully selected by its sovereign and built according to the standards set forth by the council of Manta priestesses. Each fortress was erected beneath a dome of air, and each sovereign received a trident, forged in the ocean's deepest depths by the Manta priestesses. At the centre of every hemicycle, a chamber was installed, containing a diorite casket within which the priestesses sealed each trident. Niptus, of the House of Dyonistos, was appointed Emperor of the seven kingdoms, and for a few years, they lived in peace.

It is said that the warming of the sea brought on the nerves of the underwater tribes. Yet, thanks to the Avilone Channel, which separated it from the Lorimean Sea, the northern ocean remained still quite cold. However, the water temperature, the twilight, and the currents of the environment in which each had chosen to settle led to different evolutions among the peoples over the generations. These inequalities in evolution induced tensions and various power struggles, punctuated by opportunistic murders. Eventually they drove the kingdoms to isolate themselves.

Emperor Niptus of Dyonistos had been negotiating a fresh peace agreement for months when a treacherous and deadly creature from the Lorimean Sea, "a Seasoul", dislodged Niptus'trident from its stone sheath, disrupting the balance of water and air. The protective dome of Dyonistos 'kingdom shattered, causing its citizens to drown. The tragedy was of such magnitude that it terrified the other clans. Together, the remaining six Houses sealed the Avilone Channel, the only known passage between the Northern Ocean and the Lorimean Sea, and signed a non-aggression pact.

Times went by, under a peace weakened by centuries of resentment, betrayal, armed conflicts and by the worsening warming of the waters, which every day, seemed to fuel more fears and animosity between the members of the six remaining kingdoms. . .