I have to admit I rarely use surprise as it seems a pain to adjudicate, but I'm facing the upcoming scenario in my campaign.
The PCs will be fleeing a collapsing fortress along a long causeway, where a group of cultists is waiting to ambush them. The cultists are hidden behind various battlements and buildings of a ruined gatehouse, and have cast a glyph of warding at the end of the causeway.
The PCs have no reason to suspect the ambush and will presumably be focused on fleeing until they trigger the glyph of warding. The glyph is the signal for the cultists to rise up and engage the PCs.
My thinking is to not give the PCs any sort of perception check until the glyph is triggered, which initiates combat. Those that roll high enough notice the cultists as they spring the ambush and get an action in the surprise round, while those that fail the perception check do not.
Do I have this right or is there a better way to resolve this?
Surprise
When a combat starts, if you are not aware of your opponents and they are aware of you, you’re surprised.
Determining Awareness
Sometimes all the combatants on a side are aware of their opponents, sometimes none are, and sometimes only some of them are. Sometimes a few combatants on each side are aware and the other combatants on each side are unaware.
Determining awareness may call for Perception checks or other checks.
The Surprise Round
If some but not all of the combatants are aware of their opponents, a surprise round happens before regular rounds begin. In initiative order (highest to lowest), combatants who started the battle aware of their opponents each take a standard or move action during the surprise round. You can also take free actions during the surprise round. If no one or everyone is surprised, no surprise round occurs.
Unaware Combatants
Combatants who are unaware at the start of battle don’t get to act in the surprise round. Unaware combatants are flat-footed because they have not acted yet, so they lose any Dexterity bonus to AC.
You're supposed to do an opposed PC's Perception vs Ambushers' Stealth check, and make sure you include +1/10 DC to the Perc check for every 1 foot the Ambushers are away from the PC's while they're hiding (so if the Ambushers are 40ft from the walking path and their stealth roll was 35, the DC to spot them would be 39 because they're 40ft from the PC's). And the PC's should get a Perc check to notice the Glyph of Warding prior to triggering it (DC25 + spell level), so for a lvl 3 Glyph of Warding, the DC would be 28 (+1/10 DC to the Perc check for every 1 foot the PC's are away from the glyph), so this could end up being a 31 DC if the PC's are 30ft away.
If you really want to get froggy with the +1/10DC math: PC's are 30ft from the Glyph in the walking path, and the Ambushers are 40ft on either side of the glyph, so the Hypotenuse of the PC's to Ambushers would be 50ft, so it should be a +3DC to the Glyph DC, and +5DC to the Ambushers' Stealth DC. <---- this is the most proper way to do it, but I understand some tables don't like playing Mathfinder.
Anywho personally, I would do both Perc checks for the Glyph and the Ambushers Stealth prior to the Glyph being triggered, as to give the PC's a chance to avoid the ambush altogether, or to even partially mitigate the effects of the ambush by being able to have 1 or 2 PC's act in the surprise round.
So there's 4 scenarios that can happen:
If the PC's fail both checks, they would 1) trigger the glyph, and 2) get ambushed and not be able to act in the surprise round.
If the PC's fail the glyph check but 1 or 2 PC's pass the Opposed Perc v. Stealth, they would trigger the glyph if they continue to move towards it (they might stop after noticing the ambushers though). The Ambush would probably get triggered anyway at this point because they were noticed, so any PC who passes this Opposed Perc v Stealth would be able to act in the surprise round, and any PC who fails would not be able to act in the surprise round. There's a decent chance that the PC's will trigger the Glyph during the ensuing combat because they didn't notice it. And the Cultists might even fight from the other side of the Glyph in order to bait the PC's to come trigger it. (The cultists can set the Glyph to allow passage to anyone who speaks the password, or even to automatically allow passage to anyone in their religion/cult, so they could stand on top of it without triggering it if you want, but they can't be in the area when it gets triggered or they will take damage)
If the PC's pass the glyph check and fail the Ambusher Perc v Stealth check, they would probably stop before triggering the glyph, which again would probably trigger the Ambush anyway. The Ambushers might wait to spring the attack until they attempt to disarm/dispel the glyph or try to go around it. The PC's would not be able to act in the surprise round.
And if the PC's pass both checks, they would stop in front of the glyph, and if the ambushers attack, then any PC who passed the Perc vs Stealth check would be able to act in the surprise round, while any PC who failed the Perc vs Stealth would not be able to act in the surprise round.
================
Things you can do to prevent metagaming:
A Failed Perc Check (for either the glyph or the Ambushers' Stealth) reveals that there is something going on behind them, such as someone Chasing them, or someone behind them is loading a Ballista, or attempting to mount horses, or the collapsing fortress chunked out a section of the causeway behind them, w/e you see fit.
If they fail the perc checks for the glyph and/or ambushers, you have to make it seem as if they "passed" the perc check by feeding them distracting information as to not rouse their suspicions of an ambush, because doing 2 Perc checks usually = something bad up ahead, and if they know they failed because you say something like "you notice nothing out of the ordinary", they might metagame and say something like "I search for traps and ambushers".
Holy cow, that is one detailed analysis! Thank you for putting so much thought into that, although it kind of supports my notion that adjudicating surprise is just too damned complicated! :)
Yes, if you break it down, detecting the glyph and the ambush are technically separate issues, but my sense was that passively detecting a "nearly invisible" glyph (as per RAW) while running to avoid a collapsing building didn't make a whole lot of sense, unless they maybe roll a natural 20!
Regarding the ambush, I realize it should be an opposed perception vs stealth check, but whose stealth? There are technically 4 different creature types with different stealth checks making up the ambushers. Do I roll a stealth check for each creature type and use the lowest, since that would be the easiest for the PCs to defeat? Or, roll stealth for each individual ambusher to compare against each individual PC's perception check? Talk about crunchy!
yep, separate stealth checks for each ambusher, vs a single perception check for each party member. it will basically boil down to lowest stealth vs each party member.
Holy cow, that is one detailed analysis! Thank you for putting so much thought into that, although it kind of supports my notion that adjudicating surprise is just too damned complicated! :)
Yes, if you break it down, detecting the glyph and the ambush are technically separate issues, but my sense was that passively detecting a "nearly invisible" glyph (as per RAW) while running to avoid a collapsing building didn't make a whole lot of sense, unless they maybe roll a natural 20!
Regarding the ambush, I realize it should be an opposed perception vs stealth check, but whose stealth? There are technically 4 different creature types with different stealth checks making up the ambushers. Do I roll a stealth check for each creature type and use the lowest, since that would be the easiest for the PCs to defeat? Or, roll stealth for each individual ambusher to compare against each individual PC's perception check? Talk about crunchy!
Yeah, technically you're supposed to make x1 roll for each Ambusher's Stealth (so 4 rolls), and technically, each PC is supposed to roll against each Ambusher individually.... but that's dumb. No sane DM on the planet would make their PC's roll 5 Perc checks all in a row while trying to set them up for an ambush and a trap, meanwhile the DM is making 4 unprovoked, mysterious rolls as well. PC's are going to know something is up and instantly stop and sniff your trap/ambush out.
You should make it even easier on yourself and just make one roll for the Ambushers using whichever mook has the lowest Stealth. If they notice even 1 ambusher, then they act in the surprise round. So, the highest 3 stealth checks don't actually matter, in theory.
Also, check out Perception for Perception Modifiers. Your specific situation could have a pretty high DC Modifier due to "Creature is Distracted" because of a collapsing building and "Terrible" due to the noise of the collapsing building.
|
Yes, if you break it down, detecting the glyph and the ambush are technically separate issues, but my sense was that passively detecting a "nearly invisible" glyph (as per RAW) while running to avoid a collapsing building didn't make a whole lot of sense, unless they maybe roll a natural 20!
Perception (and stealth) are skills, so rolling a natural 20 doesn't and shouldn't do anything special.
Rolling a natural 20 is dumb luck, having a high (or low) perception score is a player decision.It is always a good choice to award (or punish) the player choices.
As an added factor, there are classes that have a bonus to the surprise perception roll, so not making it or having it succeed only on a natural 20 penalizes those classes.
About the complexity and numbers of the rolls:
1) the cultist can take 10 (or even 20, if they had someone check their position and they did spend a lot of time positioning themselves). There is no need to roll for the cultists;
2) the rules aren't clear about what is the stimulus to allow someone to make a reactive perception check. It can be the single ambusher or the ambush as a whole thing.
I am inclined to think it is the second thing. When you use perception to scan a room, you don't roll once to notice the hidden door, once to notice the out-of-order book, once to notice the locked chest, and so on and on. You roll once, with different interesting things having a different difficulty.
In the ambush scenario you mentioned, you can have something like:
- DC of spotting the Glyph 28 (in the spell description);
- DC of hearing the cultist* (assuming they are completely hidden from sight) 20 for taking 20 (extremely well-prepared ambush), +1 for the cultist dexterity, no skill, chain mail -5 = 16;
3) circumstance modifiers:
for hearing the cultist +5 to DC, terrible conditions, the fortress is crumbling;
for both the cultist and the glyphs: distracted, the PCs are running for their life +5 to the DC.
End values:
DC of hearing the cultist 26;
DC of spotting the glyphs 38.
At this point you have the players roll Perception for their characters.
The PCs that barely make the roll to hear the cultists know that there is someone/something there, so you share only that information, and only when they are in the ambush area.
The PCs that beat the roll to hear the cultists notice them 10' earlier for each point above the minimum needed. If they notice that a full move before getting into the ambush area they can alert their companions.
Same thing for the glyphs, only that the DC is higher (and some PCs can have specific bonuses for that).
Written it seem complicated, but in play, it is simple and rewards the choice of having a high perception.
*The number for the cultists is only an example. If you have 4 different creatures, each creature should have a listed value for its modified stealth bonus.
You still have a fixed value, as it is a prepared ambush and the NPC can take 10 or 20.
Taking 10 is a great friend for the GM.
I think Diego has it right except that he hasn't taken into account the perception modifier for being behind the walls and the distance modifier. Lets add another +20 for the terrain modifiers and distance. This brings the cultist DC up to 46, which is higher than the glyph's DC and makes running the encounter a lot easier. Also, when designing an ambush it would make sense for the trigger to be the easier to spot than the ambushers otherwise the ambushers are likely to be spotted before hitting the trigger.
With the modification above and to clarify what I think Diego is saying. I would roll the Perception checks when the glyph would be triggered but before telling the players the glyph is triggered. If the glyph is spotted before being triggered I would wind back to the distance where the glyph would be spotted. At this stage I expect the players would request a second perception roll to see if they can see anything else and I would roll that in secret (even if not asked) to determine if they can see the ambushers. If the glyph is not spotted before it is triggered then the ambush would proceed as designed.
Interesting how many perspectives there are on a simple ambush! I hadn't thought of the take 10 or 20 option, thanks for that. The cultists know the party has been in the castle for some time and have been waiting for them to prevent them from making off with a McGuffin, er, weapon, so they are well prepared.
Thanks for all the feedback - I'll come up with something that works!
^---- Pizza Lord is right, the Perc check only applies to that one PC and per each check vs. the glyph or the ambushers, and also I would not give the ambushers take 20, but take 10 is entirely reasonable, and the glyph itself cannot take 10 or 20 obviously.
Per RAW, there should be an individual check vs. the glyph and each of the ambushers, and like I said before, this is dumb. This represents so many unprovoked rolls that your PC's will undoubtedly metagame.
But a PC that notices either the glyph or the ambushers also has a Free Action to shout "STOP!" too. So in the interest of fairness to the PC's, I really do think that the PC's should get separate Perc checks vs the glyph and vs. the ambushers, but out of fairness to the DM I don't think they should get 5 Perc checks vs. the 1 Glyph + 4 ambushers. Do one perc check for each, 1 PC check vs. the glyph, and 1 PC check vs. the ambushers. The PC's are kinda screwed by the time they'd be making these checks anyway, so allowing them some skill checks to alleviate this situation is entirely warranted. I think when all is said and done, your PC's will appreciate the fairness of this ambush/trap you've set them up for.
You could even "amp up" the encounter by having the causeway deteriorating in major sections behind them, taking away any valuable "retreating" or "kiting" ground and environmentally forcing them to move forward into the fight or otherwise fall with the collapsing causeway.
If the ambushers have 2 minutes to prepare, which it sounds like they do..
They most definitely can and would take 20 on stealth.
In addition, if they have total cover then they can't be seen at all and it doesn't matter.
I dunno. Maybe if the Cultists are trained in Stealth, then maybe yes. Taking 20 on a stealth check is a GM call due to the opportunity for lots of failures to make it "perfect". And even then, there's still an opportunity for failure, regardless of how good at "stealth" you are.
Taking 20When you have plenty of time, you are faced with no threats or distractions, and the skill being attempted carries no penalties for failure, you can take 20. In other words, if roll you a d20 roll enough times, eventually you will get a 20. Instead of rolling 1d20 for the skill check, just calculate your result as if you had rolled a 20.
Taking 20 means you are trying until you get it right, and it assumes that you fail many times before succeeding. Taking 20 takes 20 times as long as making a single check would take (usually 2 minutes for a skill that takes 1 round or less to perform).
Since taking 20 assumes that your character will fail many times before succeeding, your character would automatically incur any penalties for failure before he or she could complete the task (hence why it is generally not allowed with skills that carry such penalties). Common “take 20” skills include Disable Device (when used to open locks), Escape Artist, and Perception (when attempting to find traps).
Ability Checks and Caster Level ChecksThe normal take 10 and take 20 rules apply for ability checks. Neither rule applies to concentration checks or caster level checks.
|
|
^---- Pizza Lord is right, the Perc check only applies to that one PC and per each check vs. the glyph or the ambushers, and also I would not give the ambushers take 20, but take 10 is entirely reasonable, and the glyph itself cannot take 10 or 20 obviously.
Per RAW, there should be an individual check vs. the glyph and each of the ambushers, and like I said before, this is dumb. This represents so many unprovoked rolls that your PC's will undoubtedly metagame.
Per RAW, it is one check for each stimulus. Totally undefined if the stimulus is every single ambusher or instead is the ambush as a whole.
Seeing how is used in other instances (as an example searching a room) generally, you check once for the whole situation, not once for each noticeable item.
I really do think that the glyph and the ambushers ought to be treated as two separate events that provoke Perc Checks.
This is both in the fairness of the PC's as well as the DM. And I can prove it with... *hands you a plate of nachos*.... evidence.
|
|
I really do think that the glyph and the ambushers ought to be treated as two separate events that provoke Perc Checks.
This is both in the fairness of the PC's as well as the DM. And I can prove it with... *hands you a plate of nachos*.... evidence.
I fully agree with that.
The glyphs are a trap, the guys doing the ambush are creatures.It is a rule of thumb, but generally I will separate the stationary, inanimate objects from creatures that possibly breathe, are tempted to peek from behind the concealing wall to see if the targets are approaching and that can give their position away in ways that will not affect objects.
Often PCs abilities will give different modifiers against different creature types or categories of objects.
Some specific creatures, like Caryatid columns, have a special ability that gets them treated as objects.