On the nineteenth day of Black Library’s 2016 Advent Calendar, James Swallow’s short story Exocytosis oozes onto our e-readers, the penultimate Horus Heresy story in the collection. Amidst the forests of Zaramund, Luther and his Dark Angels offer aid to the battered forces of First Captain Calas Typhon, but there’s little trust between the Angels and the Death Guard. Plagued by unsettled, troubled thoughts and unsure what to make of the slow changes coming over his body, Typhon waits while repairs are made, whiling the time away in restless contemplation. Meanwhile the Dark Angels watch and listen, making their own plans.
If you don’t already know the destiny of the Death Guard this should give you a clue (hint: exocytosis is roughly defined as secretion)! Swallow paints Typhon as dour but not emotionless, at a point just before the next major step in his development but only partly aware of what’s about to happen. It’s an interesting setup, especially using these two Legions, and the narrative nicely plays on their contrasting mindsets and outlooks. Perhaps it could have done with being told over a novella instead to really delve into Typhon’s big moment, but it nevertheless sets things up interestingly for what’s to come next.