Tooru is the only relative Kamui left during his childhood days except his aunt Tokiko that he just meet during his return. Even though Kamui’s mother, Shirou Tooru, dies just before the start of the story, she is one of the story’s most influential characters. It is because of her and her sudden death that Kamui returned to Tokyo and it is her words to him about his love for Kotori and Fuuma that inspire him to choose to protect the Earth.
Tooru cared deeply for her only son and hated the fact that he was burdened with such a cruel fate. As she was burning up, her final words about him were, “Sorry Kamui… I must die, leaving you alone with this cruel fate. Kamui, be strong so that you can choose the future.” Although she believed in fate and generally accepted it as immutable, she also hoped that Kamui would be able to overcome his fate and save the world. Despite generally telling Kamui about his fate and giving him information that would be hard for a child to process, she also withholds a lot of information, specifically concerning the Holy Sword and the Monou family. Perhaps she thought that her information, of which she had a lot, would influence Kamui’s decision and jeopardize the future. In any case, it seems that she had a lot of faith in her son’s heart and his desire to protect those he loves. It seems she really wanted Kamui to be happy, no matter what that meant for the future.
For his part, Kamui loved his mother deeply as well and wanted to protect her as much as Kotori and Fuuma. She had to explain to him that her fate was already set, she would have to die, which was difficult for him to accept. Her death marks an important turning point in Kamui’s life because she was the one person who had always been on his side and who he trusted completely. Her death furthered his isolation and intensified his need for other friends on whom he could depend, meaning her death as well as her instructions to return to Tokyo drove him right into the middle of Monou family and his destiny.
Magami Tokiko is Kamui’s aunt and Tooru’s younger sister. She was only a young teenager when her sister lefts while she was pregnant with Kamui, but she was still tied inevitably to his destiny. In time she got a job working as a public health official at the school Kotori, Fuuma, and (eventually) Kamui all attend and she lived in a house very close to Kamui’s old home. Once Kamui returned, she sought him out in order to tell him about his family legacy, of which he knew nothing. In fact, he never even knew that his mother had a sister. At first he was completely confused about her identity until he realized just how much she looked like his mother. Unfortunately she was taken before she could give Kamui very much information and as she was pulled from her house, she told Karen, who had been observing Kamui’s old house, to burn her place to the ground.
Although this does not become clear until much later, she was taken by agents working for Hinato who wanted to keep her from giving birth to the second sword. Eventually she escaped her captures, but she was badly wounded in the process. She came to Kamui while he was with Fuuma at the Togakushi Shrine—the same place where Saya died giving birth to the other holy sword. After telling Kamui that she was happy with her fate, her body ripped apart as she gave birth to a second sword. Kotori sees her body torn into pieces and begins to lose her mind.
Tokiko is in the story very briefly and gives Kamui little information, though it is unclear how useful this information would have been in the long run anyway. Her death results in Kamui possessing the second sword as well as his decision to become a Dragon of Heaven.