Kor'sarro Khan: Huntmaster (Black Library Advent Calendar 2013 #4)

On the benighted world of Gehöft, the White Scars battle the forces of Chaos, both mortal and daemonic. As plague spreads and darkness reigns, Kor’sarro Khan takes to the field, eager to take the head of the traitor responsible for the world’s corruption. But when his Dark Angels allies abandon the fight, the Khan and his bikers are forced into a deadly confrontation with the servants of Nurgle that threatens to damn them. Read it because
It's a short but well-crafted tale that sees the Khan's speed and lust for battle used against him, and sets up a confrontation with the Dark Angels.