Codex: Imperial Knights (2015), p60 — House Krast

The treachery of the Horus Heresy took a fearsome toll on Chrysis, with the traitor Titans of Legio Mortis the chief culprits behind the utter ruination of their home world. House Krast was the only knightly house on Chrysis to survive the calamitous events. So great were their losses that only their proximity to Mars, and the great support of the Fabricator General, allowed House Krast to recover. Since that time, the Nobles of House Krast seek the forces of Chaos above all others, hoping to settle old scores and fulfil oaths sworn by every one of their ancestors. Despite this, House Krast still honours Mars, and never shirks its responsibilities to its Adeptus Mechanicus allies.