RulingRules Reference 1.7

If an enemy initiates an attack against Black Panther but another hero or an ally defends against that attack, will…

Question

If an enemy initiates an attack against Black Panther but another hero or an ally defends against that attack, will Black Panther’s retaliate ability trigger?

Answer

No. Black Panther himself must be attacked for retaliate to trigger.

— Rules Reference 1.7