As leader of my Dark Side Adepts, Military Executioner Sedriss has been my most loyal and is commended for reviving me here on Byss. But for all his usefulness. Sedriss is only a moderate Force-sensitive, a capable errand boy but hardly the stuff of a Sith apprentice.- Jedi V Sith: Essential Guide to The Force
Although I feel like this might be contradicted, at least as far as moderate ability goes. I mean unless it's all relative.