AncientMermaidmon

AncientMermaidmon is an Ancient Aquatic Beast Man Digimon. Possessing the attribute of "Water", it is one of the Ten Legendary Warriors that saved the ancient Digital World. A Mega who existed only in the distant past, it is the guardian goddess of the birthplace of Digimon, the "Net Ocean", ruling the whole of it and able to handle all water, such as the ocean currents and tidal waves, as if they were its own limbs. It is said that countless continents and islands have been erased when AncientMermaidmon felt angry. Its abilities were later passed on to the "Aquatic Digimon".

Attacks
 * Great Maelstrom: Generates a gigantic which swallows everything in the water.
 * Crystal Billow: Crystallizes water into s, then fires them off like a machine gun.

Etymologies
Official romanization given by the Digimon Reference Book and used in Japanese media.
 * AncientMermaimon (エンシェントマーメイモン)
 * (En:).

Name used in the American English version of Digimon Story: Cyber Sleuth and other American English media.
 * AncientMermaidmon
 * (En:).

Digimon Story: Lost Evolution
AncientMermaimon is #278, and is a Mega-level, Balance-class, Aquan-species Digimon with a resistance to the Water element and a weakness to the Thunder element. It possesses the Confusion Barrier, 7 Lucky Gods, Item Master, and Digimon Professor traits, and it has the special skill Dive.

It dwells in the Angler Tunnel. When defeated, it can drop the debug plate for AncientMermaimon.

AncientMermaimon digivolves from Mermaimon. In order to digivolve into AncientMermaimon, your Digimon must be at least level 46 with 220 attack, but only once you have revived AncientMermaimon and input the Spirit of Water.

It can be hatched from the Aqua DigiEgg.

Digimon Story: Super Xros Wars Red and Blue
AncientMermaidmon is a Mega-level Digimon. It can be digifused during battle from Mermaimon, Whamon, Scorpiomon, and Coelamon, and will attack with "Great Maelstrom". It can also be formed from a DigiMelody.