Demetrios was a scout in the army of the Byzantine Empire. He was a handsome blond man in his early 20s, born in Thessalonike. Demetrios was serving on the Danube frontier in 1305 AD when hypostrategos Andreas Hermoniakos ordered the army to cross north into the steppe country for a punitive mission against the Jurchens. He and his commanding officer, Basil Argyros, were scouting ahead and found the hoof prints of a half dozen unshod horses, indicating a Jurchen scouting party. On reporting this, the army went on alert in preparation for battle.