Got an opinion on the theological difference between "being saved" and "demon possession"?

Came up in another thread. Got me to wondering.

Terminology for your perusal prior to response:
– Born again
– Spiritual possession
– do your own Google search

Last thing I’m trying to do here is push a religious agenda. If you’ve got input to the semantic, etymological differences or if you have personal insight and experience, bring it on.

Don’t like the topic, then move on.

Very interested in viewpoint from agnostic, atheist, pagan, secular, whatever belief systems… although I expect that the various flavors of Christian denominations have their say.