Had a revelation earlier today: Thieves establish surprise dominance. In case it wasn’t clear, “surprise dominance” is when you aren’t surprised but you surprise your enemy, thereby getting a bunch of bonus attacks on him without them alerting their friends. And, this applies most in 1E D&D, less in 2E and 3E.
Here’s why I say this: Open Locks, Move Silently, Hear Noise.
Open Locks lets you open a door without making any noise. If you fail your Open Locks, you didn’t get through the door, but you also didn’t alert any monsters inside. Once the door is unlocked, you can have any member of the party open it and the rest rush in to attack a potentially-surprised opponent.
If you don’t have Open Locks, you have to break down the door using Open Doors (STR). If you fail to Open Doors, you alert the monsters inside and they can’t be surprised – and if they have multiple rounds of warning they can set up defenses or call for reinforcements. You might be able to get up to 3 people in front of a door for Open Doors, ensuring a good chance to succeed and still possibly surprise monsters, but all of those PCs used their actions trying the door so none can take advantage of the first combat round. Fewer bashers means lower opening chance but more available attackers if you DO get it open.
Open Locks takes time, which is the downside to using it. Time spent means more wandering monsters.
Move Silently allows a Thief ahead of the group to better surprise a monster. Silent movers like Giant Spiders and Elves / Halflings in non-metal armor surprise 4 in 6 instead of the normal 2 in 6. In 2E the surprise roll is on d10 and unlike 1E, you can be surprised for only 1 round. In 1E you’re surprised for the number of rounds shown on the die (so a Giant Spider surprises you 4 in 6, if you roll 3 you’re surprised for 3 rounds but if you roll 5 or 6 you’re not surprised at all).
(Yes I know it’s actually “surprise segments” but they act like rounds except for spellcasting and it’s easier to not explain that).
Here’s the thing: your Thief can surprise the enemy, then call for help and the PCs can race forward to take advantage of the surprised monster. They lose a round of attacks against it, but potentially a Thief can give several rounds of surprise.
Your DM might make the PCs roll for surprise, possibly eliminating one or two of these surprise rounds. He might also just say this trick doesn’t work for some reason, though it seems like that’s how the rules are supposed to work and it does make scouts worthwhile.
Backstab is basically a Move Silently ability since you can’t move while Hiding in Shadows. Backstab is how a scout can take huge advantage of surprise. Let’s say your scout surprised a guard for 4 rounds. The scout gets four whole rounds of backstabs on him, since he’s surprised the entire time and can’t do anything about it! And those attacks are all at +4 to hit and double to quintuple damage! Assassins or Fighter/Thieves can even backstab with big-damage weapons like Two-Handed Swords.
Silent movement takes longer, which is why you wouldn’t sneak everywhere.
Hear Noise (something Elves and Halflings are also able to do though they don’t improve at it) lets you hear if something is behind a door or down a hallway. If you succeed, you can’t be surprised by the thing, but you can still surprise it.
Because there are notes describing Hear Noise as not working against certain monsters (Undead never make noise etc), I’d say you’re still going to roll surprise if things are not as they audibly seemed. For example if you enter the Thieve’s Guildhouse and you hear some people inside talking, but in an alcove over the door are hidden guards, you would still roll for surprise because your Hear Noise didn’t catch the guards. Same with hearing some Orcs in a room but then you bust down the door and see a line of Skeletons standing between you and them.
Hear Noise, like Open Locks, also takes time. You might want to sit around listening at a door a bunch of times just to be sure, but maybe you should just pick your 3 best listeners and have them do it once. There’s also the occasional Ear Seeker or Mimic-disguised-as-door that can ruin a listener’s day.
A party without a Thief comes upon a door. Their Halfling tries to Hear Noise but has a 2 in 6 chance. They choose to break down the door, but either they use one breaker and fail or use multiple breakers and then can’t do many attacks against any surprised monsters. They also attract monsters from nearby rooms by breaking the door.
A party with a Thief gets a good chance to Hear Noise, possibly eliminating PC surprise. Then he tries the lock, and has a chance to open it quietly so almost everyone gets to attack. Even if he fails to pick the lock, he can sneak around and try to find another entrance and pick that one. If he slithers into a room he has a much better chance to surprise enemies and can surprise them for many rounds.
The Thief’s surprise dominance skills are very situational. In a wide-open wilderness his abilities could be a lot less useful, especially Open Locks, although in anything but plains and tundra the Thief should be able to do some Move Silently / Hear Noise. They’re also a lot less important as you get into 2nd Edition and especially 3rd Edition, mainly because in those games surprise is a thing that happens for only one round. In 3E backstab is replaced with Sneak Attack, which any Rogue worth his salt will get on every attack in every combat round.
As I wrote in an earlier post about Surprise in 1E, Elves and Halflings basically get 100% Move Silently because of their racial stealth ability. As for this post, they also get a small Hear Noise bonus but the Thief will eventually get better at it and become the most reliable listener. Of course nobody else gets Open Locks although an M-U with a Staff of the Magi (or is it Power?) who gets free Knocks makes Open Locks useless … exactly how many such staves exist in the whole world?
In all, the 1E/2E Thief really is combat-oriented, in a way that beefs up the whole party, just in a very subtle way. He’s also very powerful in a hand-to-hand fight, but again in a very subtle way. When people look at a Thief’s stats and claim that he’s underpowered, I think that’s partly because the DM’s adventure design diverges from the expected norm (few locked doors, not using surprise rules) or the player doesn’t take advantage of his abilities (staying in the rear, not scouting, refusing to pick locks because he’s afraid of traps). The Thief was simply diluted in 2E (lower Thief skills, surprise rules nerfed) and redirected completely in 3E.
I think that given the above, a party lacking a Thief is really missing out. A party of all-Thieves could be pretty interesting, but a balance is probably better (such as a Cleric for healing / light / rations, a Ranger to improve the party’s surprise roll and help in the wilderness, an M-U for combat magic and identifying magic items, Fighters for reliable damage output and reception).