Doctor L. Arx

Doctor L. Arx grew up Retrograde in the Iron Works, which meant growing up mistreated. With a visibly decayed face and the wrong bloodline, Arx was considered repulsive by nearly everyone. The exception was a Pureblood girl named Eileen, who treated Arx with a kindness that had no obvious motive. The two became friends: platonic, enduring, and for Arx, defining. When Eileen fell seriously ill, sick enough to die before the Gravemind restored her, the experience broke something in Arx and rebuilt it as purpose. Arx became a medic, then a Graverobber, determined to prevent the kind of suffering that had nearly taken the one person who mattered.
  That expertise made Arx irreplaceable. The infection-enhancement process that Arx designed allowed Iron Works officers to sustain greater infection levels, making them harder to permanently kill. Without Arx, the entire program would collapse, and the Full Dead strategist E. Koch knew it. Koch also knew that Arx harbored moral objections to the Iron Works' treatment of Irons and the institution of slavery. To keep the Graverobber loyal, Koch recruited Eileen to serve as a handler, lending a sympathetic ear to Arx's concerns while ensuring the work continued. Arx never suspected the manipulation.
  The spy T. Vars identified Arx as the Graverobber most likely to defect, and the assessment was accurate. Killed at least twice during the Fall of the Ironworks, Arx returned each time due to enhanced infection levels. In the Mortis Amaranthine, Arx was open to joining the Uprising but insisted that Eileen must be part of any arrangement, or that Arx must first be convinced to let her go. On a second encounter, Arx offered to sabotage Koch's program entirely, provided the Uprising could give sufficient reason to abandon the one bond that had kept the architect of Iron Works immortality chained to a cause Arx despised.