Apsu

Apsu is a demon appearing in the series.

History
Apsu, also known as Abzu or Apzu, is the primordial deity of the watery abyss and the deification of the vast primordial fresh water beneath the earth that appears in the Babylonian creation myth, Enuma Elish. He is the source of knowledge and was the lover of Tiamat, the embodiment of the salt water. Together they created the first gods. Apsu could not quell the noise of the younger gods. He colluded with his vizier Mummu to silence the gods and allow him and Tiamat to rest. Their plan to exterminate the unruly younger deities was stopped by Ea, the god of wisdom. This narrative bears some resemblance to the conflict between Enki and Enlil in the earlier Mesopotamian flood myth, though there it's humans rather than younger gods who are in danger. Later Tiamat battled Ea's son Marduk to avenge Apsu.

Apsu (or engur in Sumerian) was also the name for fresh water from underground aquifers which was given a religious fertilizing quality in Sumerian and Akkadian mythology. In later Babylonian mythology, the underwater apsu was understood as the remnants of the entity Apsu, harnessed by Ea (Enki) after their battle. Lakes, springs, rivers, wells and other sources of fresh water were thought to draw their water from the apsu. Many gods were said to dwell in its waters, including Enki, his mother Nammu, and the fish-like apkallu sages. In Hurrian and Hittite mythology, an ancient tool used to separate the earth from the heavens was said to be hidden somewhere in the apsu; Enki retrieved it to remove the evil giant Ullikummi from Ubelluris' shoulder to help his ally Teshub, the storm god. In various myths, Enki creates animals, people or mythical beings out of clay from the apsu.

The city of Eridug, which was the center of Enki's cult, was traditionally believed to be built atop the apsu.

Appearances

 * Shin Megami Tensei IV: Deity Race
 * Shin Megami Tensei IV Apocalypse: Deity Race, Boss
 * Ronde: Shin Akuma Race
 * Devil Summoner: Soul Hackers: Godly Race, Boss
 * Shin Megami Tensei Trading Card: Card Summoner: Godly Race

Devil Summoner: Soul Hackers
Kaneko's design for Apsu's hands draws inspiration from this particular clay figurine of Mesopotamian origin. The figurine is meant to represent Astarte (though it could possibly, but less likely, be Asherah).

Shin Megami Tensei IV Apocalypse
Revived by Inanna, Apsu is a required boss in the Cosmic Egg.

Devil Summoner: Soul Hackers
Apsu is one of the two ancient demons inhabiting the ruins beneath Nikamimon, the other being Tiamat. Their presence interfered with the Phantom Society's plans of installing Manitou at the site, so Vice-Minister Nishi hired Naomi to eliminate one of the demons to make room.

During the associated Vision Quest, the player must choose whether Naomi eliminates Tiamat or Apsu. If Apsu is confronted, upon his defeat he curses Naomi and kills her as he dies. The god's power is later absorbed by Manitou, which gives it strong physical attacks but a vulnerability to magical attacks.