Spoiler warning! This article contains plot details about an upcoming episode.
Takayuki Ujiie was the chief instructor at Gokumon Private School, and also Shuji Aino's father.
History
His son Shuji was a hard-working and well-mannered child, and Ujiie loved him very much. He later joined his father's institution. Unfortunately, because he was a sincere student, Shuji was severely bullied. After his tragic death, his father was grief-stricken, and was burning with anger and disgust at his students. Since they could never be brought to task for all the things they had done, he wanted to kill them himself. The Puppeteer from Hell took advantage of his state, and planned for him the 'perfect murder' for revenge.