What was a mythical beast during Middle Ages that stood for death and sin and was the most feared beast?

The mythical beast that embodied death and sin during the Middle Ages was the dragon, often depicted as a fearsome serpent-like creature. Dragons were associated with chaos and destruction, representing the ultimate evil that knights and heroes had to confront. Their fierce nature and association with hellfire made them symbols of death, sin, and the struggle between good and evil in medieval lore. These creatures frequently appeared in legends, signifying the moral battles faced by individuals and society.