As the last surviving member of her family, Touka is responsible for her younger sibling's well being. After Arata went missing she took the burden of raising him in order to follow her father's footsteps. However, Ayato is devastated and bitter towards humans for how their prejudice against ghouls had torn his family. In turn, he has taken a different stance from his father and sister's view on them. He left Touka when she further pursued a pacifist life with humans by going to school. While he disagrees with her ideas on humanity, he still cares for her safety even despite joining Aogiri. Proved by when he refused to let Yamori and Nico to take her as well as Kaneki. As noted by Kaneki, Touka was emotionally hurt when he turned against his only family.