The Nihilist

It all means nothing. Show your opponent how pointless this whole charade was from the beginning. Winning and losing isn't about cubes, it's about the mental game. How much damage can one do to the Psych of the other player.

Show them that when the world burns you won't just be laughing, you'll be setting more fires.

Success is paved on the blood and bones of the weak, they weren't meant to survive this world anyways. Use their corpses to climb higher and higher towards the unknown. Where you end up doesn't matter, the only thing that matters is how many people you killed getting there. 

Also you get to power out a beefy Knull, Death, and/or Death+Zola on turn 6. That's pretty cool to I guess.