Additionally, I think this manga is going to expand on the other characters' guilt and their own path of atonement. I mean, we've seen it already in small hints like Shiika visiting Yuri's grave and paying respects to her shrine. I'm guessing what she feels at the moment is something like "I'm sorry for what happened to you and I feel responsible and so I promise I will take care of your brother as if he were my own" while the mother feels guilty for not being able to protect either Kazuma or Yuri and is atoning herself by being a parental figure for orphans and currently trying rebuild her family with Shiika and Kazuma