Inquisitor Marcas Tullus, is an aging inquisitor, in the twilight of his career, and as such has taken a young inquisitor by the name of Tamhas Adrien under his wing. Tullus has travel the length and breadth of the imperium in search of answers, and is a member of the Xanthism, a radical faction of the Inquisition who believe in studying and understanding the power of chaos, and turning it to constructive purposes. While this is at odd with many an Inquisitor, especially the more puritan aspects of the organisation, it is seen by the members of the faction as the only way to ensure the survival of man.
Tullus has repeatedly been drawn to the Segmentum Pacificus by the turbulent nature of the segmentum and the events that have unfolded there in recent history, including the night of a thousand rebellions. With the instability and the unusually high level of chaos taint within the area, the chances for study are almost limitless. Horatius Adrien, although a relatively young inquisitor, has already shown remarkable zeal for the Xanthism cause. It is for this reason that the older inquisitor has taken the young man as an apprentice, to guide him and teach him, so that he may continue the work tullus has started. It is also to ensure that he does not stray too far from the path of righteousness in to the darkness.
The view of many of the Xanthities does not meld well with other parts of the Ordos Xenos, and also with the Deathwatch, this has led to many forming alliances of their own. As a result of these differences, it has been necessary to maintain a small force of loyal servants to act as both a bodyguard and also a strike force should the need arise. Tullus has over the years amassed a number of servants from a variety of different backgrounds to act in such a manor. Due to the fact that the inquisitors' work brings them in to contact with many forces of chaos, including the possibility of chaos marines, Tullus has recruited those most skilled with both blade and shield. Those who have shown exceptional skill with a blade have been armed with power swords and those who have shown extreme stubbornness have been given shields, so that when combined these units can defend the inquisitors from even the most skilled and determined foes. In addition to these units, a smaller number of men, who are skilled with a rifle have also been recruited and armed to take on foes less determined. All of the servants in Tullus’ service own both their lives and loyalty to Tullus for many of these warriors, especially those whom skill lies with sword and shield have been recruited from within chaos cults, and in exchange for their lives that have sworn an oath to protect and serve Tullus. The exceptions to this are those who were recruited for their prowess with a rifle, for many of these were recruited from the ranks of the imperial guard and various PDF's.
Tullus and a number of other Xanthities that operate within the segmentum pacificus have formed an alliance with the Emperors Disciples, with who share similar ideas and opinions. As a result of this alliance, the two have fought many battles together and currently the 15h company of the Disciples along with a number of AM and MT forces are currently requisitioned by Tullus for the investigation of chaos taints across parts of the segmentum and in particular the areas of the sabbat worlds that are on the edge of the crusade that is occurring there.