The fourth member of the kill team is an Imperial Fist wielding a Heavy Bolter.
This gun was used during the Siege of Terra.
It is shoulder mounted to fired over the parapets of the Imperial Palace and is of a larger caliber than a standard heavy bolter.
He is a First company Vet with artificer armor who is determined to be better than ever other marine.
He is always competing with the Ultramarine in every way possible.
He has been in the Deathwatch for a long time