How does Volibear Imposing's ability trigger? Specifically: (1) Does Volibear need to be on a battlefield to trigger? (2) Does it trigger when you Charm an opponent's unit, or when an opponent Charms your unit?

Ruling: Volibear triggers when he is on a battlefield AND one or more units controlled by an opponent move to any other battlefield. "Opponent" refers to enemy units (units controlled by your opponent), not the player issuing the move command.

Sequence:

• Volibear must be on a battlefield (not in base)
• When enemy unit(s) move to a different battlefield than Volibear's, the ability triggers
• If multiple enemy units move simultaneously, draw only once
• If multiple enemy units move one at a time, draw for each move

Nuances:

• Charming an opponent's unit to move it DOES trigger Volibear (you are moving an enemy unit)
• An opponent Charming your unit to move it does NOT trigger Volibear (they are moving a friendly unit, not an enemy unit)
• The trigger looks at which units are moving (enemy vs friendly), not who is issuing the move command