If my opponent uses Hidden Blade targeting my Darius and I respond with my own Hidden Blade targeting Darius, do we both draw 2 cards or just me?

Ruling: Only you draw 2 cards. When the opponent's Hidden Blade resolves, the target is no longer legal so there's no controller to draw from.

Sequence:

• Opponent plays Hidden Blade targeting your Darius
• You respond with your own Hidden Blade targeting Darius
• Your Hidden Blade resolves first, banishing Darius and you draw 2 cards
• Opponent's Hidden Blade resolves but has no legal target, so no one draws

Nuances:

• Hidden Blade has the controller of the target unit draw cards, not the player who cast Hidden Blade