Kol's smirk and sarcastic mood had faded when Shiro asked the question. His face was now expressionless. "Simply put: I grew too powerful for my own good. Collector angles have to potential to become much more powerful than your keeper would have you believe. I was one such person who figured that out". Kol turned around and took a few steps towards the base of a nearby tree. He stared up at the beams of light piercing through the thick canopy. "Have you ever wondered how exactly your powers worked? How they did what they did, and what their specific effect was? Well, I wondered that. I was always curious as to how we could collect souls. For a long time I had wondered, until one day when I was collecting a soul that I realized. The soul I was collecting was determined to stay where it was. As I recall, the soul wanted to stay in the house that it was born in. I however, was determined to bring the soul for judgment. I thought I would have trouble when I touched the tip of my scythe upon the soul wisp, but I received to feeling of defiance. However, the soul was furious after it was already within the soul cylinder. I had then realized, our ability to collect the souls, was a type of manipulative ability. The length of that ability that every collector is taught is the command to move the soul to another location. Though we are never told that we are actually manipulating the souls against their will. That was when I asked myself a question". Kol was now starring at the shadowy ground and said "If I can command a soul to move to another location. What if I could command a soul to accompany and obey me? I was now determined to prove my theory. Though, I was still devout im my charge and I would never have used an innocent or uncertain soul a test subject. So, I instead used the souls of wicked men. People who lived in crime and sin. People who had no chance of passing judgment. I collected several of those souls and began my experiments". The shadows around Kol began to darken and churn until they took on the image of molten tar. "After many tried and failed experiments, I had managed to successfully gain control of one of the souls. I was able to use it to scout out areas and find souls that I could not immediately sense. I had originally intended for this ability to be a use for all collectors. If we could all have a wisp to help us in our searches, we could find and collect souls before the demons could ever get near them. However, That was not the end of my experiments. My wisp was too fragile. I had often lost and had to replace these wisps on account of them being attacked by particularly stealthy or intelligent demons. So, I tried to figure out how to increase my wisp's strength. It wasn't long before I had figured out a way. I had, by that time, mastered the manipulative ability that we possessed and figured out that I could potentially command the soul to do anything. I gathered a fair amount of souls, all criminals and other unredeemable people of course, and placed them in a small space. Once they were all in place, I gave my wisp the command 'devour the others'".
as Kol explained, the tar-like shadows began to produce nebulous bits of demonic essence that seemed to me acting out the souls being devoured by Kol's wisp. "Once my wisp had finished assimilating the others, I could sense a tremendous increase in its strength. It had grown powerful enough to take on other forms. Soon I had done this process with many other wisps and had gained control of a large amount of them. However, I had started to become reckless, and became more focused on seeing the full limits to this power. That was when the Keeper finally noticed what I was doing. But he panicked, and thought I was becoming corrupt and intent on taking over the Heavens. So he, and several archangels stripped me of my rank as a collector and banished me from the Heavens. I had become exiled to the underworld where my wings and my soul became tainted and blackened by the demon miasma and my burning hatred for the angles. Though it was in the underworld that I gained more power than I could have ever imagined. I not only perfected controlling souls, I figured out how to mold them and make them more powerful and intelligent". As Kol's story was coming to a close, the shadows slowly began to revert to their normal state. "Now you know why I was banished. All because someone feared the possibilities of what we could become. You have the very same potential as I did when I was still a collector, but you are not the kind of person that could control the soul of another". Kol walked up to Shiro until he was just a few inches away from her. His black feathered wings blocked out what light was shining on the angel before. "In the end, banishing me was probably the best thing for me. I was now free to continue my practice unhindered and unseen. I even figured out how to combine angelic and demonic essence. It is that fact that my essence is not being rejected by your soul, or the soul of your companion. But now you know my story. So what is your thought on this? I was never given anything resembling a trial, so I am curious to hear the opinion of one who had no knowledge of this".