When he his firing his laser, just attack him from behind. He will always fire inward and so won't ever hit you. By doing this, you can get high combos very quickly
Loved this game, though a pure black deck is way too powerful.
5 Blackguard Veteran
5 Blackguard Leader
5 Disintegrate
5 Memory Serpent
5 Drain Life = Win
Just power up until you have 4 mana, then keep drawing cards