Ancient Binahus is a great hero of the chapter whose mortal body was reduced to a thick meaty paste by Orks one afternoon.  His brain, bits of nervous system, and a few rashers of crispy marine bacon were interred into a dreadnought so that he could fight on.  But his dreadnought is also his chapter’s secret shame.  Don’t tell anyone, but this Steel Guard paintjob hides an earlier Ultramarines job!  Can it be that the Steel Guard have yoinked one of their allies’ dreads?