Copper: The Power Within is the tenth Secret Mission in DmC: Devil May Cry. At the beginning of the mission, Dante will automatically use Devil Trigger. He must then defeat all 9 Stygians before the Devil Trigger duration expires. Each enemy defeated will restore some Devil Trigger gauge.
It is recommended to pull the enemies towards Dante using Demon Pull and then use Eryx' Brawler ( / ) to easily defeat the enemies.