

Defeating even the prodigious Ayane, Raidou eventually manages to mimic the technique from Hayate, and rendered the boy both comatose and paraplegic before escaping.

When Kasumi was seventeen, her uncle, the rogue ninja Raidou, returned to the village to obtain the Torn Sky Blast technique a ninpo spell used by the clan's leaders. However, once Ayane learned of her true heritage, and the children now knew that they were siblings, Kasumi's friendship with Ayane ended due to Ayane's jealous anger over her mistreatment by the clan, centering her animosity on the "princess" Kasumi.

Her relationship with Hayate was also ideal, with the two playing games and training together happily. According to their mother, Ayame, Kasumi and Ayane used to have fun catching fish for the family. From childhood, Kasumi has lived a privileged life full of expensive clothes, servants and the respect of the rest of the Mugen Tenshin clan. When they were children, Kasumi and Ayane - unaware that they were related - played together as best friends, although the clan saw Ayane as a "cursed child" and didn't want Kasumi to be around her. Kasumi is the daughter and second child of Shiden and Ayame, and was born into the Mugen Tenshin's head family, making her second-in-line to the title of clan leader, after her older brother Hayate. Template:Spoiler Childhood File:Young Kasumi.png
