A Brother’s Confession by Robbie MacNiven acts as a prequel short story to the forthcoming novel Blood of Iax and introduces the characters of Kastor and Polixis (geddit?), two Ultramarines Primaris Marines whose bond of brotherhood goes deeper than Chapter ties alone. Apothecary Polixis comes before Chaplain Kastor to make a confession, relating to his brother the tale of his last mission, and the sin he committed.
A small, self-contained story, despite the slightly on the nose character names (see here) this manages to be both a nice setup for the upcoming novel and a satisfying (albeit brief) exploration of Kastor and Polixis, their roles and the nature of Primaris Marines in the Ultramarines. If that sounds a lot, it’s all quite lightly covered, but with a few snippets of conversation and a rapidly-told set piece MacNiven fits plenty into a short space of time. There’s already a sense of character to these Primaris Marines – the Fulminata – a century after their induction, with an expected degree of familiarity but enough to set them slightly apart from ‘normal’ Marines. Meanwhile the protagonists’ relationship shows immediate promise, suggesting that there should be plenty to look forward to when Blood of Iax lands.