(Voice type: medium-low, low)

Considered the primary antagonist in the series, his name is derived from the French word for "thirteen". A calm, calculating man, Treize is a complex individual, playing both the chivalrous, anachronistic knight and the ruthless tyrant. On the surface Treize is cold and reserved, rarely letting his emotions get the best of him. He professes a love for war, believing that when properly conducted, it brings out the best in humanity. He expresses an interest in honor and chivalry comparable to that of an old-fashioned aristocrat, believing that one should settle matters of honor in single combat, and considers himself a gentleman. This is juxtaposed with his ruthlessness in pursuit of his ambitions and his utter lack of scruples when it comes to holding onto power. Beneath the surface, he is fanatically loyal to his friends. He dislikes hurting people, and suffers a great deal of guilt over the deaths he has caused. He also seems to have some difficulty recognizing, and dealing with, his own emotions.