Sira was in a terrible state, she was meaning towards Kris her whole life, he was more than family to her, and their relationship was so close to the point where she never questioned herself if there may be a time when they would go on separate ways .
he always drove her whenever she had to kill demons, it was her job and he was always preparing before that too.
Sira didn't attend college like her sister because of her responsibilities towards the clan but he never made her think that she was less smart or worthier of his time .
he went outside in the past , he went to college and did his military service , and he saw the world outside of that countryside but he never made her think that she was less educated or experienced than him .
he was always there, therefore when he said that he was no longer going to be her assistant she felt like he killed her from the inside and took her soul and run away .