Typhus

The First Captain

Calas Typhon was First Captain of the Death Guard during the Great Crusade and the closest of Mortarion's lieutenants. He was a competent commander, ruthless even by Death Guard standards, and — what was less widely known — a closet sorcerer. Mortarion had banned psykers from his Legion absolutely; Typhon practiced sorcery in secret throughout the Crusade and assumed his primarch would never find out.

Mortarion did find out. Eventually.

The Destroyer Plague

When the Death Guard's fleet was stranded in the warp during the Heresy and the Destroyer Plague began killing the Legion at unsustainable rates, Mortarion blamed his Navigators and ordered them killed. The plague had, in fact, been delivered by Typhon — who had bargained with Nurgle in secret and engineered the crisis to push Mortarion into accepting the Plague God's offer of salvation.

The bargain Typhon had arranged worked. The Death Guard became Nurgle's Legion. Mortarion, when he understood what his First Captain had done, was unable to undo it. Typhus, as he was now called, became the senior Death Guard sorcerer-officer in defiance of every doctrine his Legion had previously held.

I gave you to him because we would have died otherwise. You may thank me at your leisure.

— Typhus, attributed to Mortarion

The Destroyer Hive

The Destroyer Hive — a swarm of warp-corrupted insect-daemons that lives in Typhus's armour and emerges to consume the bodies of his enemies — is, in Nurglite theology, the physical seat of Typhus's rank as the Plague God's Herald. Every Plague Marine sergeant's Plague Champion title traces back, in lineage, to a fragment of the Destroyer Hive Typhus shared with the warband's founder.

He is more daemon than Astartes by M42. The line is thin enough that some Imperial pathologists have argued Typhus formally crossed into Daemon Princehood centuries ago and has been concealing the elevation. Typhus has not commented.

M42

Typhus has been independently active in the Era Indomitus — operating sometimes alongside Mortarion's Plague Wars, sometimes separately, sometimes (the Imperium suspects) at cross-purposes. His leadership of the Plague Fleet that descended on the Cadia subsector during the 13th Black Crusade was a major factor in the Cadian Gate's eventual collapse.

He and Mortarion no longer speak directly. The Death Guard accept this as normal Legion politics.