Sym was the then-Commissar Ibram Gaunt's personal Adjutant in the Hyrkan Eighth Regiment during his time serving with them. He was a middle-aged, slightly overweight but effecient man with a livid burn over his throat and cheek. He had a good standing with Gaunt and was chosen to accompany him to Tanith after the victory at Balhaut.
When Tanith was attacked by a Chaos splinter fleet, Sym stayed with Gaunt to the end. He barred two Tanith militiamen from obstructing his commanding officer's entrance to a waiting cutter, even as the Elector's Palace burned and fell all around him. However, one of the militia men became angry and shot Sym, before Gaunt could drop them both. Gaunt was about to pick Sym up when the man turned and shielded Gaunt from a burst of shots from a close group of Chaos warriors Gaunt hadn't spotted, and died protecting him.