Vienen (They Come)

The usual jig for me : punishing someone because he have done an action tend to be more defensive than offensive, and defensive is not wanted at the moment.

Then again, it's far from being useless on the offensive, not alway useable but often enough.

Also, playing this in addition to pentex can be pretty mean. Maybe add a way to prevent playing both ?

No. Incredibly broken.

nice card picture but broken text.

3 pool to remove a threat for 4 turns. Even it the cost was 6 pool you would find this card to be a must have in many decks.

Insanely broken. Additionally in shape of master card, meaning no interaction

can't understand the fluff-idea of the card. Who and where does come? A short explanation would be nice.

Vienen
cost X.
Master: out-of-turn.
Only usable when a vampire's action would be successful. Turn the acting vampire and cards on him face down out of play, canceling the action and breaking any temporary control effects. Put this card in play. During his or her untap phase burn this card and return this vampire to his or her controlled region, tapped. This card costs X pool, where X - half of the acting vampire's capacity (rounded down).
- 0..5 cost (depending on vampire's capacity)
- 1-2 turn "vampire turn off"

other variant:
- cost X - number of Vienen in your ashheap
- controller of acting vampire can burn 1-2 pool to cancel this master