Tanimoto Kaede was the younger sister of Tanimoto Natsu, the ex-Six Fist of Ragnarok. Kaede and Natsu were orphans until they were adopted by a wealthy business man. Natsu worked hard to be the best heir his step-father could be for his sister, who was born with a deadly illness. When the step-father finally took Kaede to one of his medical facilities, he fell in love with the female doctor working there and married her. For a brief period, the family of four were happy, with even the step-father sincerely smiling. However, the peace was short-lived, as the step-father was found dead one morning, though the police were unable to confirm the cause. The police immediately suspected the step-mother as the culprit and took her away, leaving Natsu to run the company by himself. Sometime later, Natsu discovered that the step-mother never really treated Kaede's sickness and that her condition had worsened. While on her death bed, Kaede's final words were for her brother to never give in.<br /> <br /> Kaede's death and final words, along with his step-mother's possible deception and his rescuing from Hondo by Ogata Isshinsai, drastically altered and corrupted Natsu's innocent personality. This, along with his master Ma Sougetsu's training, made him into a cold hearted, ill-tempered individual. Later, when he meets Shirahama Honoka, he finds many similarities between her and his sister, and the two develop a very sibling-like relationship, though Honoka's clumsiness and childish nature frequently gets on his nerves. Kaede's last words also made him determined never to lose a single fight, which acted as motivation for him during his second fight with Honoka's brother, Kenichi and later in his death match with Chou Enshin. <br /><br />