Dominions 3: The Awakening/Nations/Atlantis

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

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

Atlantis - Middle Age
The Kingdom of Atlantis is fighting against Oceania and R'Lyeh which seeks to enslave the people of the seas and the whole world. The Atlantians have units armed and armored with weapons and armor of poisnous coral. They are led by Kings of the Deep who are water mages of great power and the Queen Mothers who are great priestesses of the kingdom.

Atlantis - Late Age
The Kingdom of Atlantis fell. In the chaos a number of Atlantians fled to a forgotten coast of bones and ice and made a pact with a forgotten god. Atlantis turned to necromancy and magics of the frost and they are ruled by the Angakut shamans who wield powers over the dead 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.