I've been reading some of some of the supplemental books for UA such as The Statosphere, and I noticed that some of the NPC stat blocks have a (S) after one of the stats. For example, Ellison Blanke, Agent of Solace has it after her Speed stat. What does this signify?
It's how the first edition rulebook handled initiative for GMCs.
From page 52 of Unknown Armies, 1e: