Koushaku Chouno  

Papillon, 蝶野攻爵

In the Busou Renkin series, Koushaku Chouno is an antagonist who plays a significant role in the plot. He emerges early on and becomes the main villain until the L.X.E. appears. Despite appearing sinister and sickly, with "eyes like rotten river sewage," his ultimate goal is eternal life. His intense desire for immortality stems from a debilitating disease that weakens his body significantly.