Not necessarily that particular variety of entity, but certainly I have met dark entities with no internal light.
>Could it be considered Darkness instead of an entity?
In my view Darkness is the direction of the energy-intelligence, towards separation and density. Darkness is the out-breath of the Source of All. Light is the in-breath drawing back to the Source. The out-breath and the in-breath occur jointly and rhythmically and can be depicted as yin and yang.
From this you may see that Darkness is a necessary part of Existence.