Typhus the Traveller, Herald of 
Nurgle, Host of the 
Destroyer Hive is a 
Chaos Space Marine of the 
Death Guard legion.
History 
After the Heresy, The Space Marines of chaos wore a lot of spikes and carries some pretty strange weapons. Before the Heresy, most of them wore plane armor save a few. 
Calas Typhon, the future Typhus, was one of those few. Really, you've got to wonder a little about your buddies when they start carrying giant scythes and wearing spikes on their face. 
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| Heresy-era Typhon | 
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This is actually rather telling. According to 
Lexicanium and the novel
The Flight of the Eisenstein, Typhon willingly turned to Chaos before his Primarch 
Mortarion or even before the fall of Horus. He was converted to Chaos by 
Erebus, 
First Chaplain of the 
Word Bearers and used those powers to climb the ranks of the 
Death Guard legion to the dizzying heights of 
Captain of the 1st Company, the highest rank second only to that of the Primarch himself. By virtue of his rank, he was given undisputed command of the battleship 
Terminus Est a massive and powerful battleship.
His original name is also rather telling of his personality. "Calas" is a homonym of 
callus and 
callous. A callus is "... toughened area of 
skin which has become relatively thick and hard in response to repeated friction, pressure, or other irritation." This is certainly a good characterization of 
Typhus both before and after his fall.From what I remember of him from 
The Flight of the Eisenstein, he was constantly irritated by everyone including his Primarch. He hated Battle-Captain 
Nathaniel Garro and would have killed him in an instant if he had the opportunity to get away with it. If he had only known the troubles that Garro would cause (the escape and resultant humiliation, warning the Emperor and founding the Grey Knights), Typhon would have slain him regardless of the consequences.