Can I play Cull of the Weak while I control no units and my opponent controls 1 unit?

Ruling: Yes, you can play Cull of the Weak even if you control no units while your opponent controls units.

Nuances:

• Cull the Weak has both players make a choice on resolution, so you don't need a valid target to play it
• If you can't perform the instructions (because you have no units), that won't stop your opponent from performing their part of the effect