Can the Vampiress drain the life force from "bad" followers, too? By bad I mean followers that say you must accept them as a follower, they do detrimental effects to you, and are discarded in special ways (eg: Vagabond, Poltergeist, Deathstalker, etc.)

I should say: yes you can do that.

But if you draw the hag, then you still lose all your other followers, and then you can drain her

Velhart said:

I think so too. I think the ability of the vampiress will ovewrite that of the hag.

What life force would a Poltergeist have that the Vampiress could drain?

No to the Hag & Poltergeist, yes to all the others.

ever heard of "etherical essences"?!^^...

The Wizard said:

There's already a thread where the answer was given by Talismanamsilat, who's involved enough with the development of this game to give non official answers before they become official. Just in case you don't know him.

Even though it seems to contradict statements like "you cannot voluntarily get rid of bad Followers", such as Hag, Jester, Vagabond and Poltergeist, the Vampiress ability has been ruled legal towards those Followers. Still you cannot prevent the Hag from discarding all your Followers, but after that you can immediately jump at her wrinkled throat.

We've been waiting about one and a half year for a new FAQ... when are we going to get all the clarifications until Sacred Pool?

Shifting Spirit said:

No. Should I?

Do vampires have the ability to drain "etherical essences"? Are there any examples in literary history to base this assumption on? If so, then I guess she could drain the "life (read etherical essences) force of the Poltergeist.

well, I dont' have any - but how do you know that a ghost doesn't have some kind of "life force"?