I think Kazuku was trapping team Kakashi with his tentacles, then use the Fire+Air combination. So team Naruto use the WindRasegan+Water Combo to cancel it. Kazuku probably release the tentacles during the attack, otheriwise he would be buring himself.
It feels funny, almost cheap, that Kazuku's masks act like weapons - no seal needed to release wind, fire, lightning...His earth and lightning hearts are gone, his other one could be water?
Killing time while waiting for the next chapter. OnePiece, that is.