Equip Fradz with +Critical Damage as high as possible and give him a Wind Walk (Invisible Strike), Aderline Rush on Fradz and then Sword Dance on him, you would like to buy some Siphon Life also.
Now is the stragedy:
-First 50% just use all the spell with both Phodom and Fradz on him.
-He should pernament spell immune when he has 50% hit points left.
Now
do
{
-Use Fradz crazy DFS and Wind Walk on him.
-When he disappear, use Fradz's Dark Power which you steal from chapter 2 on the mere creeps. Some Blade Storm and Phodom's spell if that dark power is not avaiable.
}
while(the Vampire's hitpoints > 0)