If I use Overzealous Fan's ability to target an enemy unit with Deflect to send it back, do I have to pay the Deflect cost?

Ruling: Yes, you must pay the Deflect cost. Overzealous Fan's ability targets an attacking unit as part of its effect, and Deflect applies to spells and abilities that choose a unit with Deflect.

Sequence:

• When Overzealous Fan's ability triggers ("When I defend, you may kill me to move an attacking unit to its base"), you choose whether to use it
• If you choose to use it, killing the Fan is the cost within the instruction
• Moving an attacking unit to its base is the effect, which requires choosing a target
• The target must be chosen when the ability goes on the chain
• If the chosen unit has Deflect, you must pay the Deflect cost at this time to place the ability on the chain
• If you cannot or do not pay the Deflect cost, you cannot choose that unit as a target

Nuances:

• The cost within the instruction ("kill me") does not involve targeting
• The effect portion ("move an attacking unit") does require targeting because it involves choosing a game object in a public zone
• Deflect applies because you are choosing an opponent's unit with an ability you control