Why that house? Well as they prepared and mustered to join the emperors crusade at the side of Horis. Imagine to their surprise when Mortarian of the Death Guard turned up, kidnapped the head of the House and then secured the venerable house to support the Death Guard. Of course as he left he virus bombed the planet to express his thanks.
And they sport the croased hammers and as a born and bred West Ham supporter that is most excellent
So here it is with some additional markings to express their loyalty to the Plague Marines