The eldest son of the Sumimura family, Masamori is 21 years old but appears much older. Despite being the oldest of the three brothers, he is not the heir. He leads a section within the Urakai organization and seldom returns home, but when he does, he stays for extended periods. Masamori is an exceptionally skilled Kekkaishi, adept at using techniques that are challenging to master.
His relationship with his younger brother, Yoshimori, is complex. Yoshimori often feels envious of Masamori's control over difficult techniques and how Tokine interacts with him. Interestingly, Masamori is frequently seen examining the palm of his right hand, where the mark of the "legitimate successor" is located. This suggests that he may be jealous of Yoshimori, even if he doesn't fully realize it himself. Yoshimori frequently questions why Masamori wasn't chosen as the legitimate successor.









