The Thief Skills As Surprise series (list of links below) has, up to now, dealt with surprising others, but not with avoiding surprise. This is, basically what the Hear Noise ability does: it gives a chance to find out if something is behind that door before opening it.
If there is no other proof that the skills of the Thief class are meant to be extraordinary versions of abilities any ordinary character should be able to do, “Hear Noise” should be the clincher. Anyone can listen at a door. If the noise is obvious to anyone who listens, no roll is needed. If it’s a slight noise, most characters make a standard surprise roll, but humans have a penalty on that roll:
- if using the “surprise on 5+ (1d6)” rule, humans are at -1
- if using the by-the-book “surprise on 1-2 in 6” rule, humans surprise only on a 1
- Delving Deeper expresses this as half normal surprise chances
Success on this roll means that the listener is warned. The GM should tell the player what kind of noise it is, possibly identifying the monster or device making the noise if the character has any knowledge of that monster or device. Even when unidentified, the player now knows something is behind the door and cannot normally be surprised. The Hear Noise roll is, effectively, a second roll to avoid surprise.
This assumes that nothing changes in between the character hearing the noise and opening the door or entering the room. A creature could, if alerted to a player’s presence, still attempt to surprise. For example, a band of thieves in the room could hear a character outside the door and choose to hide in shadows, negating the character’s advantage.
A thief has a better chance of hearing a noise. Add a bonus equal to half the thief’s level, rounding up, either directly to the roll or to the target number, whichever is appropriate for the system used. If using the alternate Surprise Table, don’t use either the opponent’s level or the dungeon level as the difficulty, in most cases. Instead, rate the door’s level:
- No Door: Level 0
- Standard Door: Level 1
- Thick Barrier: Level 4
- Soundproof: Level 8
If a monster is known for being exceptionally or even magically silent, use the monster’s dice or level if it is higher than the barrier’s level.
If you want to give thieves a Detect Traps ability, as some versions of D&D do, it would basically work the same way. Use the dungeon level as the trap’s level. Similarly, these rules could be adapted to other senses, such as a scent-tracking ability for werewolves. Just remember that the level of the opponent being tracked or detected never matters unless the opponent is actively attempting to prevent detection.
Thief Skills As Surprise Series: