Dominions 3: The Awakening/Nations/Atlantis

Atlantis
Atlantis is the kingdom of the Deep Ones, strange underwater creatures that resemble a mix of human, fish and toad. The Atlantians have fought Aboleths, R'Lyeh and Oceania only to be banished to a forgotten coast of bone and ice. The Deep Ones never stop growing and the oldest of them are gigantic in size. Atlantis wields great power over Water magic.

Atlantis - Early Age - The Basalt Kings
Not much is known about this era.

Atlantis - Middle Age
The Kingdom of Atlantis wars with Oceania and R'Lyeh whom seek to enslave the people of the seas and of the world. The Atlantians are armed and armored with weapons of poisonous coral. They are led by Kings of the Deep; water mages of great power and the Queen Mothers who are great priestesses of the kingdom.

Atlantis - Late Age
The Kingdom of Atlantis has fallen. In the chaos a number of Atlantians have fled to a forgotten coast of bone and ice and forged a sacred pact with a forgotten god. Atlantis has turned to the magics of necromancy and frost. They are ruled by the Angakut shamans who wield powers over death and ice. The banished Seraphs of Caelum were coerced to give up the secrets of ice weapons and now the Atlantian armies march forth clad in ice and furs.