This year's 40k miniature character based on those found in the Black Library books is Captain Uriel Ventris. This Ultramarine is getting a new mini soon, as well as some new rules. Get a look at some of those rules in this preview.
From the article:
Every year, the Black Library Celebration brings you a new model representing the hero of one of the event’s key stories. Previous years have brought the legendary Inquisitor Eisenhorn, Commissar Severina Raine, and a pair of Talons of the Emperor to life.
Today, we’re taking a look at what this paragon of the Chapter will add to your Ultramarines army in games of Warhammer 40,000.