You really don't need to over-complicate things. I'm not sure if Level 3 has changed since when I used to fight them but a deck with 12-15 Obsidian Pillars, 6 Black Dragons, 6 Devourers, and 3-6 other things (e.g. Steals, Dusk Mantle, Nightfall) was excellent. In my opinion, Minor Vampires and Drain Life are not so useful.