For millennia, Heaven has always remained peaceful. Even when Lucifer fell, Heaven remained a place of peace and beauty. Even as good and evil battled on earth, the angels continued to do their duties—the seraphim praised and sang of God, the cherubim guarded Heaven's gates, the guardians continued to protect prophets of God and the archangels remained the most powerful of them all. Yet, in 2080 CE, the balance between Heaven and Hell shifted as more and more souls descended into Hell. Through a rip in the space continuum between Heaven and Hell, demons attacked Heaven and killed countless angels.
The archangels, as powerful as they were, couldn't fix the rip. They appealed to God but He did not answer. Thus, the archangels came together to decide a course of action. One of the archangels, Raphael, suggested that they create another species of angel to fight the wicked demons. As a result, a small group of angels called the La'ziel were created. Unlike any other angel, their wings were as black as night, their eyes red as crimson and their soul as charred as ashes. Because of how different they were, the other angels quaked and shunned them, creating a rift that would last for decades.
The La'ziel were driven by a war instinct called Warfire that not only numbed their pain when they fought but stoked their endless hunger for spilled blood. They lost their Warfire and felt pain after a battle but while they were fighting, they were the ultimate warriors.
Unfortunately, this ruthlessness came at a price. The La'ziel would never be able to feel love outside of war. They could care for their fellow La'ziel, the ones who they battled with. They could feel satisfaction, lust, happiness and sadness, regret, and guilt. But not love. Love was taken away for the price of Warfire. This was the price they paid.