Well, the last time, I sent a single invisible character with a wand of
cloudkill and the boots of speed around to the right of the symbol in
the floor. Hit the wand just before you see Sarevok, and then pop into
conversation range. Sarevok will talk to you and then attack. Run back
to your party, which should summon creatures and undead as you come.
Sarevok will then get caught up in the swarm you have summoned, allowing
you to pelt him with ranged weapons and spells. Any time the crowd gets
thin around him, summon more.
