Twice Critical

Twice Critical is a commonly occuring Sacred Gear (known as the Dragon's Hand in the anime). It doubles the power of the user for a certain time. Reynalle mistaken Issei's Sacred Gear to be a Twice Critical. Seigfreed of the Hero Faction uses a Sub-species of Twice Critical where he grows a Dragon Hand on the back of his body. His Balance Breaker creates 4 Dragon Hands.