If you are playing a mage, necro call will be your friend in this battle (at least one of many friends you could use
). Take out his necromancers (if there are any in his army - for me, there were 2 stacks) with ranged units/spells and necro call them (necro call lvl3, possibly with necromancy, raises a lot of necromancers). Karador resurrecting his troops shouldn't be a problem anymore for the rest of the battle