So I have an adventure . . .

[darthauthor]

Heroes have a necromancer.

The deal is, the necromancer summons a vampires (usually wild). The heroes set a trap for the vampire(s) (1d4; typically wild vampires).

They slay the vampires.

Rince, Wash and repeat.

How long can they keep doing this?

I figure the scondary vampire who made the wild vampires has to know they are dead.
After a half dozen or so, do they bother to investigate who is summoning them?
Do they dismiss the vampire deaths as wild vampires so no big deal?
Is it only when a secondary vampire gets pulled into the summons that the master who made them starts to pay attention.

Thinking like a master vampire (or at least a secondary) I'd make more vampires or send vampires and human allies with the next vampire who gets summoned. Follow him. Spring our own attacked on the heroes. We, as the vampires and their human pets, would not know how many heroes there are, they weapons/magic/etc. but I would either send in a scout to witness the ambush of my wild vampire I created or launch a full on attack depending on my dispostion and mood.

Also, figure a dispell magic or something would free the vampire from the summons.
Would it?
What if I, the secondary or master vampire, staked my own vampire. Waited a week (for the duration of the spell to wear off) then pulled the stake out?

What would you do?

[Ice Dragon]

Send search parties out to find the necromancer, who summons my wild vampires or but trackers on my vampires, if I'm a clever master vampire.

Track them down, attack with packs of wild vampires under the command of secondary vampires.

Other approach by a clever master vampire, hire a band of mercs or other player band to find the summoning necromancer and take him out - search and kill mission.