Despite his loyalty and politness, he does have an ugly side, his temper which he obvioulsy gets from his father. When Tsuyohsi loses his temper, he loses all control of himself and enters into a beserking rage that is nearly unstoppable (except by a karate chop to the top of his head applied by Hayama ). Tsuyoshi rarely loses his temper unless it has to do with his somewhat jealous feelings of Sana, whenever he sees Sana's affections directed towards somebody else usually sets him off.