Petros Orsini, also known as il Ruinante or the Knight of Destruction, is the Chief of the Department of Inquisition and an supporting character in Trinity Blood. As an inquisitor, he is addressed as Brother Petros. He is shown to be rather violent with an intense hatred for vampires, and extremely dedicated to the pope, although he is not beyond showing reason or compassion. The novels mention that he is of Roman high noble birth.
Brother Petros is a man with a strong sense of honor. He is a hot-headed man who is fiercely loyal to the Pope Alessandro XVIII, believing everything the young boy says to be amazing and is easily moved by the Pope's words. It is said in manga and novels that like all other members of the Inquisition, Petros actually has a doctorate degree and has a sharp mind. Although he appears to be quite a serious character in the anime, he is rather humorous character in the manga and novels.