All of these demons can be confusing. Here's a little information that might help with understanding Sumerian demons. All gods have a silent character before their names. This is the Dingir symbol. So Enki is really d|Enki and Enlil is really d|Enlil. After the founding of the Order of the universe all gods who have a place of authority over an aspect of the Order are gods.

Everything that is not a god is an Udug. Udug are Sumerian demons. A god in another pantheon is not simply a Dingir. It is either an Udug or, if it is given a place of power under the Order of the Universe then it is a Dingir. Galla, Maskim, Ala, and Lilitu are all types of Udug demons. Annuna and Igigi are types of Dingir.

When something has Hul in its name that means that it is hostile. Demons, like humans, can be helpful or harmful. Evil is a relative term that the Sumerians didn't really have. To the rabbit the fox is evil simply because the fox seeks to kill the rabbit. To the farmer the rabbit is evil because the rabbit consumes their food. Neither the fox nor the rabbit is truly “Evil” they both have their place in the world, but that place can be at odds with the place of another.

In general Dingir have places of authority in the Order, and Udug are subservient under the Order. In Sumerian myth conflict usually happens when the Order acts upon or is acted upon by an outside force, or if something within the Order violates a law.