Matsu was close to Sokichi and always helped in his cases by researching certain facts. However, he had a slight envy of his partner always getting the girl. When he fell in love with the opera singer, Melissa after she hired him and Sokichi to save her from Kozo Yaguchi, he went as far as to use a Gaia Memory to become a Dopant in order to fulfill that request. After a few uses of the Gaia Memory, Matsu's mind warps to the point of wanting Melissa as his lover by keeping her from touching Sokichi and planting bombs on the people of Futo so that they would lose the ones they loved.