Specialty Skills (GS) represent a character's proficiency at a single, specialised skillset. Specialty Skills are only useful in a very specific situation but can completely turn the tables if employed when needed and where needed.
Characters improve Specialty Skills by spending Experience Points (XP) at a rate of 2 XP per SS, but progression is not immediate: advancement requires in-game justification, such as training, study, or practice under the right conditions. Additionally, most Specialty Skills will require proficiency in specific General Skills, a specific origin or even specific in-game events unfolding.