Does Emperor's Divide work with Blade Dancer (Irelia's ability that triggers when you target or choose a unit)?

Ruling: Yes, Emperor's Divide works with Blade Dancer. The spell targets/chooses the units being moved, not just the battlefield and number.

Sequence:

• When you play Emperor's Divide, you choose which specific units to move as part of placing the spell on the chain
• This counts as targeting/choosing units for Blade Dancer's trigger
• The units are selected before resolution, not during or after

Nuances:

• Emperor's Divide is worded similarly to Foxfire, which also targets units
• Spells like Whirlwind do NOT trigger Blade Dancer because the unit selection happens after resolution (both players may select, and it's a "may" selection made after the spell resolves)
• The key distinction is whether you choose/target units when placing the spell on the chain versus selecting units during or after resolution