Double Backfist, called Backfist Dual (裏拳二段/Uraken Nidan) in Japan, is a move used by Kazuya Mishima since Tekken 6: Bloodline Rebellion, it replaced his Demon Backhand Spin.
In Tekken 7, the second hit will trigger a Screw.
Description[]
Kazuya punches his opponent in the face with his right hand then swings it the other direction across the opponent's midsection.