They have a greater deal of autonomy than other sects within the Society, having their own monasteries and internal hierarchy.
The Sons of Tertullian draw their credo from Tertullian's teachings that anyone who stands against the Word of God must be possessed. The main targets are psychics, mediums and people suspected of trafficking with the supernatural like the Rom. In recent times, the Sons have also begun to classify the Imbued as possessed. Some of their detractors claim that the Sons themselves are vehicles for darker spirits.
The main method of the Sons for exorcisms is torture. In most cases, the "possessed" die during the procedure. The Sons know little distinction between Messenger, demon, spectre or wraith, seeing all incorporeal creatures as demonic entities that are agents of Satan. They have little knowledge of Stygia or the Underworld at large, although they have learned that some mortals can traverse it.
The leaders of the Sons are a group collectively called the Hosts, who direct the Sons from various hidden monasteries. The head is the Host of Hosts, a secretive figure who is rarely seen by anyone not in the leadership of the sect. Below are seven ranks which are ostensibly divided after talent, seniority and successful exorcisms.
- Preceptor: The Spirit of Gabriel has the task of setting sect policy and receiving orders from the Host of Hosts.
- Scholar: The Mind of Justinian has the task of learning more about the Underworld and creating artifacts that aid the lower ranks in exorcisms.
- Exorcist: Tertullian's Right Hand acts as elite exorcist for more powerful demons
- Avenger: The Holy Army of the Blessed Archangel Gabriel teaches lesser ranking Sons about exorcisms and conducts them on regular possessions.
- Special Operator: Tertullian's Eye lures ghosts for the kill and teaches the Waiting Sons.
- Diviner: The Holy Army of the Blessed Archangel Gabriel prepares equipment and conducts research if a person is possessed.
- Scout: The Holy Army of the Blessed Archangel Gabriel searches for trails of ghosts and potential possessed.
Below are the "Waiting Sons", members that have not yet been fully initiated into the group.
- Apostles of Gabriel: The Apostles train for combat against possessed and demons
- Thrice-Blessed Mendicants: The Mendicants focus on the more scholarly aspects of the Sons theology and lore
The Sons have five internal sects:
- The Disciples of Lazarus: The Disciples search for a way to resurrect those who died under the effects of possession.
- The Sickle and Crown: This sect decries knowledge as detrimental to faith and plunges into exorcisms without much preparation.
- Solomon's Sons: The Sons search for knowledge about possession and the dead.
- The Sect of Mary: The sect of Mary is a group of seventy-seven nuns prepared to commit suicide in the service of the Sons to enter Heaven.
- The Sect of St. James: The sect follows the words of a Gnostic treatise which advocates suicide as a means for entering Heaven. Their members study the spirit world and are believed to have found a way of entry.