Can you torrential tribute gorz emisary of darkness?

Yes, but not always. Remember there is only a limited amount of cards that can be activated during the Damage Step of the battle phase, and Torrential Tribute is not one of them. You cannot use Torrential Tribute in the damage step, and that is where Gorz is special summoned if you trigger him from battle damage (his token is summoned in the damage step too).

However if you trigger him from effect damage and summon him, Torrential Tribute can be used in response - unless you take the effect damage during the damage step, in which case the above still applies.