The rules text for spec-ops base units seems to contradict the base troop chart. Page 214, under "Spec-Ops, Armies, and Sectorials" When playing a Campaign, an Infinity Spec-Ops trooper can be taken with his corresponding faction army (PanOceania, Yu Jing, Ariadna...) even when using a Sectorial Army in Narrative Mode, regardless of its unit of origin. However, Infinity Spec-Ops troopers cannot be taken with a Sectorial Army which has not listed their unit of origin. For example, a Celestial Guard-based Infinity Spec-Ops trooper cannot be fielded when using an Invincible Army in a scenario of the Campaign. To me this sounds like you could take, e.g. a Ghulam spec-ops in Hassassins, since Ghulams are part of that army list. However, the big chart on page 212-213 and Army both say that the only legal spec-ops in HB is the Muyib. Am I missing something? Am I reading too much into the first paragraph of the rules?