Day 1: Perturabo: Stone and Iron.
The 33rd Grand Battalion of the Iron Warriors, newly raised and seeing battle for the first time, have the honour of the primarch himself, Perturabo, leading them. But the Hammer of Olympia is there for more than just battle – he is evaluating his new officers and deciding their fates. And with a force of Imperial Fists allied to their cause, Perturabo sees the perfect opportunity to teach his new warriors the difference between the stone of the VII Legion and the Iron of his own.
Now I am not familiar with the author, but if he is anywhere near as good as Guy Haleys interpretation of the character and the Legion, I am sold! The Primarch-stamp seems to be the overall brand for pre-heresy-stories now.