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Besides trying to kill everything elts besides the slann mage and his unit, can anyone elts give some good advice for a 2000 point game vs a slann mage player?
Vampire Counts-4000 Points
Black Templars-2000 Points
A lot of it depends on the unit in which the slann hangs out. If he's in a temple guard, it's a pain because they're going to be stubborn (and the Slann will most likely also be the BS... but on the bright side, he cannot leave a unit of temple guard. You need to try to get a high model count into the fight to win combat with outnumbering so that they'll auto-break barring insane courage... but the last thing you want to do is to put zombies in there unless you're giving them the vampire lord level helm of commandment. Saurus of any variety will eat them for lunch needing 3's and 2's, each having 2 attacks base.
If he's hanging out in a regular saurus unit, he can leave but typically won't if you have something like a varghulf running around (since they're so fast). Your best bet is to just charge the saurus unit and try to run down the slann. Now a varghulf can't do this himself, but a big unit of black knights, blood knights, or grave guard can do the trick.
Barring that, just watch out for kroxi's charging through skinks.
Could try a stonehenge. Vampire + 2 power stones + Forbidden Lore. Take lore of shadows and try to Pit of Shades his I2 ass (assuming the template will fit over the slann, anoyne confirm that?). Would need to draw out his scrolls before it could work though.
2000AD's answer to all "How do VC deal with ..." questions: Forbidden Lore + 2 Power Stones.
Further answers will require more vodka.
You don't need to completely cover the base - it's hits like a stone thrower, so anything the center hole is over gets auto-hit.