Or go an alternate direction. Iron hands hink the flesh is weak, and seek to change it through bionics and the machine. Perhaps a chapter goes the route not of the machine, but of biological improvements, drugs and surgery at first, but not for pleasure, as that would lead to Slaanesh, but for durability. They expose themselves to poisons and diseases to improve their immune system, like the old Death guard. They experiment to improve the betchers gland, as if they are immune to the toxins, they can use them against their enemies. Over time, the tenets of Nurgle slip into the chapter, perhaps through the Apothecarion.