Though he is usually able to control it, Matsu is very hot tempered. He especially hates PKers, and does everything in his power to defend people from them, including going on regular patrols to find and stop PKers. His oath as a member of Moon Tree keeps him from attacking players except in self defense, but he has learned how to taunt PKers into making the first move, allowing him to defeat them without any repercussions. He is fiercely loyal to Zelkova and Sakaki and recently developed a rivalry with Haseo.