Chapter 171: Underground Nuclear Bunker

The Blood Oath was the angels' final trump card!

This was a power that only angels with four wings and above could use. It had to be known that in order to preserve the purity of their souls, angels generally tried their best to maintain their calm and indifferent hearts to reduce their exposure to too many negative emotions. Even in combat, they had to shout slogans of justice to strengthen their will and prevent themselves from falling because of negative forces.

However, the Blood Oath was an exception. Angels were beings with free will, and they had their own siblings, compatriots, and people they cared about and valued, so they would also produce the mentality of revenge due to anger.

The Blood Oath was such a power. It could transform angels through their anger and desire for revenge into blood angels, giving them more strength to help them complete their revenge.

This was the origin of the angels of vengeance in human legends…