Sons of Malice: Combat Squad

It's been a while since I wrote an update concerning my developing Sons of Malice miniatures.  To be fair, I've only built up and painted a few of them, having concentrated most of my time on daemons of late. That not withstanding, I've got a small combat squad of Sons of Malice marines now -- enough to form the core of killteam squad at any rate.  

The five of them are converted with a variety of close combat weapons (spear, axe and mace), one has a flamer special weapon, and there are some chaos warrior bits thrown in to the mix as well. All are painted with red accents on their head pieces, similar to the initial test model that I painted up. 

I am yet to figure out the insignia for them and how to paint it.  In the Games Workshop background, it is typically depicted as a skull: one half in white, the other in black, and sometimes with an arrow down the middle of it.  I not too sold on that insignia though.  Other ideas would be welcome!