Self-mill, in most cases, is actually more powerful than milling your opponents
40 Life: Players start with a hearty 40 life, a significant jump from the 20 life in traditional one-on-one formats
Enter: Cori-Steel CutterCori-Steel Cutter, aka, one of the latest banes of Standard
Usual suspects like Reckless Fireweaver will help you out, and if you can live the dream and get an All Will Be One on the battlefield, it's all over
Like all Backgrounds, its effects are only active when you control your commander
On the other hand, Nightveil Specter can steal lands, which is a nice upside, but because it was printed nearly a decade ago, it doesn't fix our mana for the cards it steals (it's our only theft card that doesn't), so we either need to hope that our opponent is playing blue and black cards that we can cast with our mana base or hope that we can use Nightveil Specter to steal some lands of the proper color before moving on to casting nonland cards