Soul Edge
After waking up, Siegfried found the holy sword, free from its entrapment within the wicked sword, and out of instinct used it to pierce Soul Edge. The result led to both swords sealed together in a fateful embrace, an "Embrace of Souls". Siegfried took both weapons and started a quest to find a definitive way of sealing Soul Edge, but memories of his slaughters, plus the attacks of those resentful of the Azure Knight, drove his mind towards insanity. Unbeknownst to him, the evil soul of the blade escaped and obtained a temporary shell, starting a new killing spree to strengthen himself while seeking its body, Soul Edge.