please help friends I can`t beat undead

[BB Shockwave]

Agreed for most of the points. The keys to winning the battle is:

-Good unit composition. You'll want hard-hitting melee units for this battle, the "Bone" ability of the skeletons/bone dragons and the high defense of Karador makes ranged units inflict much less damage.

-Wipe out the stack of bone dragons in the first round before Karador can act. He will 100% certainly raise them - you can kill them again every round, making sure he will not cast Hypnotize or damage spells! He will always prefer the dragons to raising lower level units.

-Slow down the melee units with Ice Thorns - Black Knights wasted 5 rounds for me to get through them.

-Shamans are a key to the battle. Put totems on dead bodies (except bone dragons) to prevent raising.

-Kill everything and leave the crystal for last, then let the crystal resurrect one stack only, and use Rage Taking. Use Chargers from the gained rage, resurrect fallen stacks with this! Make sure you kill the raised stack before Karador could cast a spell when that unit gets his turn.

-I used (Level 25 paladin) Royal Snakes (with Feanora and Royal Snake ring), Griffins (Griffin Banner let me recruit more, they are your decoy/tank unit for this battle), Shamans (see above), Black Dragons (use them wisely, avoid getting hit/retaliated by strong units, use wake of fire against fire-weak troops like skeletons), Black Unicrons (good damage against undead).

[iregev]

a good setup that worked for me was:
priests, Inquistors, Necromancers, sprites and dryad.
First turn blind the necromancers and the shooters kill enemy skellies, the Necromancers raise dead twice then time back. - The enemy hordes barely made it through the gates because the shooters killed them and the necromancers raised them again.

[Ymarsakar]

A few tricks I used was to use my own necromancers to resurrect their bone dragons first. If I couldn't do that, I would step on the corpse with one of my troops and never leave.

The tanks were ancient vampires and red dragons. For the crystal, as a mage, I used a demon portal which summoned demoness, and used them to attack the crystal every round or so while the rest of my army fought off the enemy stacks.