Negative adepts

[Ashim]

Subsequent release from what? Is he/they trapped somewhere?

Of course they are trapped, albeit by their own free will decisions.
They chose to serve us by providing knowledge of the negative polarity, or negative wisdom, thus are 'held' in the astral planes of the planet, and have been bound to a cycle of physical incarnations.

Humans tend to look 'exterior' when confromted with the question of responsibility of negative actions. Lucifer 'takes the stick' for our negative actions and accumulates karma that makes it impossible to depart the planetary sphere before the job is completed.
We 'humans' must integrate our negative aspects in order to allow Lucifer to be released from his contract.