If Volibear Furious moves into an opponent's battlefield and triggers his on-attack ability, but the opponent responds with Hidden Blade (presumably removing Volibear), does the 5 damage still resolve?

Ruling: No, the 5 damage does not go through. If Volibear is not present ("here") when his ability resolves, it will resolve to no effect.

Nuances:

• The key word in Volibear Furious's ability text is "here" - the ability requires Volibear to still be present on the battlefield when it resolves
• If Volibear is removed in response to the trigger (such as with Hidden Blade), the ability fizzles