Actually, after perusing my 2e inspired thief skill houserules, they step quite a bit away from ACKS conventions (they work more like 3e’s “skills” vs. a target number of 10,15, or 20 (Judge determines which number to use based on task difficulty). It’s great for players because it’s very customizable, but it’s fiddly for the Judge when making thief NPCs for the same reason.
This one is more akin to how ACKS works, it uses the current “proficiency throw” convention. It allows for customization at 1st level by allowing the player to choose the thief’s “area of expertise.” With this house rule, comparatively speaking (houserule thief vs. standard ACKS thief), houserule thieves are overall better in their skills at low levels, about the same around 9th level, and fall a little bit behind in overall ability at the higher levels. It’s also really easy for Judges to create NPC thieves with varied levels of skill.
Houserule:
At 1st level, thieves assign each of the following levels of proficiency to one of their thief skills (excluding Climb Walls*):
1 skill @ 11+
2 skills @ 13+
2 skills @ 15+
1 skill @ 17+
When gaining a new level, each thief skill improves by 1. A skill may even go below 1+ (Note that at 14th level, you will have one skill at -2+, and two skills at 0+ by default). It’s assumed that scores of 1+ or less matter since the Judge may impose a penalty for a particularly difficult use of a skill.
*Under this houserule, the proficiency throw progression for the Climb Walls skill remains as it is in the ACKS book (there are enough proficiencies tied to it that it’s not worth messing with).
For Judges making NPC thieves beyond 1st level:
- Assign the levels of proficiency to the NPC’s skills
- Improve each skill by the thief’s level minus 1.