When I bought my second set of Betrayal at Calth I wasn't 100% sure which army I was going to plump for. I wanted to do a smaller force of around 2,000 points and I wanted to try and theme it to something from the novels. My initial thoughts was a World Eaters list I'd called Descent of the Red Angel which is taken from Galaxy in Flames. It was based around Angron coming to the surface to fight the loyalist survivors and only really needed a Storm Eagle to do. However, World Eaters are quite common and I wanted to try something a bit different.