|Affiliation(s):||Department of Inquisition|
|Manga debut:||The Gloomy Sunday|
Brother Matthaios is a Carabiniere with the Inquisition Committee. He is a calm, collected young man, with dark hair in a pageboy cut.
Francesco sends him to arrest Caterina on the suspicion of being allied with the New Vatican. After he has taken her into custody and transferred her to the Lateran Palace, he reports to Sister Paula.
He is on board the Jahoel, when Sister Paula informs him of Tres and Abel's intended flight from Rome with the Iron Maiden. To stop them, he orders Commander Cambio to engage in battle, unheeding of the Roman citizens that would die as a result. At first he wants to make it look like the Iron Maiden fired at Rome, so that he could later justify his actions as defense. But after the Iron Maiden contacted them, asking them to negotiate, he orders his men to shoot the airship. Even when Cardinal Borgia is presented as hostage, he does not stray from his intended course, until Sister Paula contacts him with orders from Cardinal Medici to stand down, because killing Borgia would antagonize the Hispanic Kingdom.