Driller tactics is needed

[Shadowcran]

4 back units:
Paladins
Inquisitors
Evil Beholders
Beholders

1 Tank:
Royal Griffins

Spells:
Phantom
Stone Skin

Have Resurrection up to 3

The Paladins are usually there to heal the back units. I group them together. For driller they need to be spaced accordingly so you can constantly move up one space every turn.

I simply send the Royal Griffins forward with their Angelic Guards. Cast Phantom on the Royal Griffins, and use Angelic Guards for those first thing(even when phantom leaves, the Guards remain). If enough mana, cast Phantom again. Keep the other units away from melee range. Don't worry about how many R Griffins you lose in main stack, with Resurrection 3 you'll get them all back, but you can stone skin them if you like.

As you can tell, you can replace the Beholders with any other ranged unit.