Lord Salutem Sicarius, the Lord of Virulence, was once a Vindicare Assassin, a lethal marksman sent to assassinate Plague Lord Phalloides Amanita. This proved to be the former servant of the Corpse God's final mistake. Like Nurgle's gifts, following his failed mission, this crippled and wounded assassin was bestowed with the eternal blessing of the grandfather of plagues. The Plague Company of Lord Amanita took him in and reengineered him. Now, instead of seeking the perfect firing position to pinpoint their quarry, he now serves as the spearhead of Pulse of the Maggots' assaults, a vector of virulence and execution.
This conversion was unplanned; Games Workshop sent me this for my first year with Warhammer+ as my free miniature. I love the idea of a corrupted symbol of the Adepta Sororitas being filled with a plagued fallen servant of the Emperor. This piece was so inspiring in terms of narrative that I felt compelled to convert a squad of Sisters of Battle into my Plague Marines, as I didn't have them yet. So far, I had only planned to use Terminators and heavy assault units for my army. This was a beautiful opportunity to begin an opposing force at home, one that my friends and family might hope to stand against my Fly Lord's chosen.