Keir lived for a long while now, he existed before, through and after the Banishment.

Before the Banishment he was extremly feral, aggressive and impulsive. Keir attacked and fought almost any creature he encountered and had a speciality for hunting humans. Due to this behavior a group of people once tried to kill him in an organized ambush, but failed. This resulted in Keir rampaging through the small town these people lived in. He slayed the entire Town which led to his title 'Human-Slayer'.

Shortly after this incident Crooks were banished from Skire and Keir with them. During this time he thought about his life...his actions...his past and how his future will be, if he continues with his aggressive behavior. He swore to himself that if he ever gets back to Skire, he will try to change his ways completly and becoming a 'good person'.

When the banishment ended and Keir could return to Skire, he tried his best to fit in, to keep his promise to himself. However some things can't be forgotten...and some people recognize him as the 'Human-Slayer'. Whether they read about it or heard the story from their great grand-parents.

Whenever someone calls him out on his pasts actions, he gets flashbacks, panic attacks and maybe even unintentionally hurts the person that does so.

When Keir met a Cccat, Acie, he had an instinctive dislike for him at first. Acie however was drawn to Keir from the start, he is a helping type of person and sensed that Keir has a lot of issues and bitterness. He just wanted to help him and eventually Keir agreedto engage with Acie. It resulted in a happy relationship where Keir tries to get along with his gentle side and Acie helps him to process his trauma.