The edimmu were a type of utukku (a type of spirit or demon that could be either benevolent or evil) in Sumerian mythology and were envisioned as the ghosts of those who were not buried properly.
They were considered vengeful toward the living and might possess people if they did not respect certain taboos, such as the prohibition against eating ox meat. They were thought to cause disease and inspire criminal behavior in the living, but could sometimes be appeased by funeral repasts or libations.
The edimmu were also thought to be completely or nearly incorporeal "wind" spirits that sucked the life out of the susceptible and the sleeping (most commonly the young).
Edimmu in Order of Ecclesia is represented as a large sea creature, very similar in appearance to an oarfish, an eel-like fish whose some species grow to measure 11 m (36 ft) in length.
The Edimmu is a strange looking creature with the appearance of an eel, with a series of tendrils running along the top and bottom of it and two pairs of eyestalks. They will poison Shanoa upon contact.
It can be killed instantly if the player manages to decapitate it, meaning the player must focus their attacks on the creature's neck in order to separate the head from the body.