On the day of Darion's birth, he was stillborn. His father Alexandros, in a hurry, rushed the baby to a nearby stream, and from the freezing water, Darion Mograine entered the world. However, the joy his father felt quickly turned to grief as his wife and mother of his children, Elena, died due to complications from the birth. When the first hint of the plague of undeath started to spread around Lordaeron, he lived in a farmhouse in Brill. With Renault, Darion secretly attended their father's meeting with the members of the Knights of the Silver Hand at the inn of Southshore, where they learned about the situation in Lordaeron, the growing number of undead, and witnessed the purification of what would later become the heart of the Ashbringer.

Along with his brother, he joined the Silver Hand at a relatively young age soon after the end of the Third War. In a battle within the plagued city of Stratholme, in which young Darion insisted on fighting, he took a serious wound and fell unconscious for a day. Upon awakening, the boy described his experience as being surrounded by darkness, before being shown a light that he followed back to life.