The Hunt for Magnus (Space Marine Battles Novella)

It is the end of the thirty-second millennium. For two thousand years, since the fall of Prospero, the Space Wolves have hunted their greatest foe, the quarry who escaped them on that benighted Magnus the Red, sorcerer-primarch of the Thousand Sons. Now, Great Wolf Harek Ironhelm has the traitor primarch's scent... Determined to finish what Leman Russ began, Ironhelm sets out to capture and kill his prey, and the Hunt for Magnus begins.

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This novella tells of the events directly before the battle for the Fang. The Thousand Sons were supposedly vanquished during the Heresy, but when one of the Space Wolves' ancient enemies is encountered on Arvion, Great Wolf Harek Ironhelm will stop at nothing to hunt them down.