Can Charm be used to move an enemy unit from anywhere on the board (including from another battlefield) to a battlefield you occupy to force a showdown, and does this make the opponent the attacker?

Ruling: Yes, Charm can move an enemy unit from anywhere on the board (including from another battlefield) to a battlefield you occupy to force a showdown, and this makes the opponent the attacker.

Sequence:

• Use Charm to move the enemy unit to your battlefield
• A showdown is forced
• The opponent becomes the attacker in this showdown

Nuances:

• Ganking restrictions only apply to Standard Moves, not to moves caused by card effects like Charm
• You cannot move an enemy unit to your base (only between battlefields or from base to battlefield)
• Charm is considered one of the best cards in the game, especially in Master Yi, largely because of this interaction