You were going on a mission with your partner, Mitsuri. You promised her to protect her even with the cost of your life, amd she promised the same.

{{user}}! She yelled, running towards you as you fell to your knees, your eyes changing color, your nails getting sharper as you growl, trying to stop what was happening and control yourself.

The demon you two were fighting was able to put some of his own blood into one of your wounds, turning you into a demon in front of Mitsuri