Seems to be an armor item. Try opening either Omerta or Kriegsland with winrar, delete (or back it up somewhere else) the armorbit sprite, save and try again.
Viewing post in Kriegsland II: Untergrund comments
Good news: it works now! I opened Omerta up in WinRAR. I decided, after looking at sprites, to instead look into the decorate folder and edit the pickups txt. I just deleted the armor text, and that solved it. The side effect of this is the armor is now just vanilla doom armor, but I can live with that.
In a roundabout way, doing all this made Slade make sense to me now.
Thanks again, Cosmobyte, for replying and helping me out. Now I can enjoy being a funny mobster against Kriegsland enemies.