House rules for thieves
by Craig AntounFor my BECMI D&D campaign, I added some house rules to how thieves work in an effort to make them a bit more versatile, including some abilities gained at higher levels.
For starters, a thief character's ability scores affected their thief abilities, as follows:
Ability Score Adjustments
Each thief ability is governed by an ability score (as listed below). Add or subtract to each thief ability the relevant ability score modifier multiplied by five (i.e. +1 gives +5%, +2 gives +10%, and so on). Remember, low ability scores will adversely affect thief abilities as well.
Open Locks (INT)
Find Traps (INT)
Remove Traps (INT)
Climb Walls (DEX)
Move Silently (DEX)
Hide in Shadows (DEX)
Pick Pockets (DEX)
Hear Noise (WIS)
For example, a thief with a Dexterity of 16 gains +10% to his rolls for Climb Walls, Move Silently, Hide in Shadows and Pick Pockets.
The thief's Read Languages ability is also adjusted by the character's INT score (base of 80%).
At 8th level thieves get the Sniping special ability, which is basically the Backstab ability useable at range with range weapons within 30'.
At 10th level thieves gain the ability to Decipher Magical Script at 80%, which is also adjusted by the character's INT score. This is in addition to their ability to cast spells from magical scrolls (still a 10% chance of failure/misfire).
At 15th level the thief gains the Deception special ability, which grants them the general skills Disguise, Mimicry, and Ventriloquism (this skill created for my campaign).
At 18th level the thief gains the Evasion special ability, which allows the thief to avoid damaging magical and unusual attacks with great agility. Basically, on saving throws against attacks that allow half damage on success, this ability grants no damage on a successful save (dragon breath, fireballs, etc.).
The Deception special ability is the only one I've been on the fence about. Otherwise, I feel the other changes I made to the thief class fit in well with the concept of the class.