Hi guys. New aspiring DM here. Our group just ran very first session, which went well but also left my head slightly spinning. Even after hours of prep, I still have questions. Figure I’ll start with a simple one here.
How do I handle the PC party surprising a group of different monsters? I guess I should mention potential spoiler alert in next paragraph.
Specifically, we’re playing the Phandelver module and the PC group successfully climbed up the fissure into Klarg’s chamber. The party and opposing monsters have the following stats:
Per the Surprise section in the DnD 5e Starter Rulebook: The DM compares the Dexterity (Stealth) checks of anyone hiding with the passive Wisdom (Perception) score of each creature on the opposing side. Any character or monster that doesn’t notice a threat is surprised at the start of the encounter.
This raises the following questions: 1) To determine surprise in this case, it seems I need to have each party member roll a Stealth check and compare to the monster’s static Perception stat. This assumes the monsters were not actively scanning for any threats, so it's passive rather than having each monster roll a Perception check. Is that correct? 2) To continue, let’s say the Rogue’s Stealth check is successful against all three monsters; but the Fighter only succeeds against Klarg and the goblins; and the Cleric only succeeds against the goblins. Does the Rogue automatically impose surprise on all three monsters? Or can each PC only attack with surprise against each respective creature they successfully rolled Stealth against? 3) How do I determine when surprise imposes Advantage? I understand that a combatant gains advantage if they attack from being unseen/hidden. So if the PCs party pops out from behind stalagmites to shoot their bows, isn’t that just like being unseen? Doesn’t the whole point of surprise indicate the ambushers were undetected, and therefore were not seen?
I believe it’s very easy to overthink these rules. I’d appreciate if you guys can help set me straight for next time. Many thanks in advance.
First issue is the wolf Ripper, that advantage to perception is a difficulty that might alert the enemy’s to your approach. In this instance I would make it simple, group stealth vs group perception. Trying to figure out individual who surprised who is easy, if all three of your PC’s individual stealth roll beat the roll or passive perception of the enemy ( whichever is greater ) that opponent is fully surprised and suffers the condition. If only one or two PC’s beat an enemy, then that opponent rolls initiative at disadvantage, because they weren’t expecting it but still had time to react.
Now that is just my take on the situation in vacuum, and others will play it differently. It’s really up to the DM to decide just how difficult it will be for the group to get a jump on Klarg.
Hi guys. New aspiring DM here. Our group just ran very first session, which went well but also left my head slightly spinning. Even after hours of prep, I still have questions. Figure I’ll start with a simple one here.
How do I handle the PC party surprising a group of different monsters? I guess I should mention potential spoiler alert in next paragraph.
Specifically, we’re playing the Phandelver module and the PC group successfully climbed up the fissure into Klarg’s chamber. The party and opposing monsters have the following stats:
Per the Surprise section in the DnD 5e Starter Rulebook: The DM compares the Dexterity (Stealth) checks of anyone hiding with the passive Wisdom (Perception) score of each creature on the opposing side. Any character or monster that doesn’t notice a threat is surprised at the start of the encounter.
This raises the following questions: 1) To determine surprise in this case, it seems I need to have each party member roll a Stealth check and compare to the monster’s static Perception stat. This assumes the monsters were not actively scanning for any threats, so it's passive rather than having each monster roll a Perception check. Is that correct? 2) To continue, let’s say the Rogue’s Stealth check is successful against all three monsters; but the Fighter only succeeds against Klarg and the goblins; and the Cleric only succeeds against the goblins. Does the Rogue automatically impose surprise on all three monsters? Or can each PC only attack with surprise against each respective creature they successfully rolled Stealth against? 3) How do I determine when surprise imposes Advantage? I understand that a combatant gains advantage if they attack from being unseen/hidden. So if the PCs party pops out from behind stalagmites to shoot their bows, isn’t that just like being unseen? Doesn’t the whole point of surprise indicate the ambushers were undetected, and therefore were not seen?
I believe it’s very easy to overthink these rules. I’d appreciate if you guys can help set me straight for next time. Many thanks in advance.
Surprise is a bit all or nothing in many cases.
The key line is "Any character or monster that doesn’t notice a threat is surprised at the start of the encounter."
A creature is surprised only if they don't notice any threat. If they notice some but not all of the threats then they are on the alert and are not surprised even if there are creatures that they did not notice.
In your example, you have three enemies.
Klarg has a 10 passive perception.
The goblins have a 9 passive perception.
Ripper has proficiency in the perception skill giving a +3 and base passive perception of 13. However, they have advantage on perception checks involving hearing or smell. Advantage on a skill adds +5 to a passive check value. In this case, if the wolf is likely to smell or hear the characters than see them (which is probably the case) then the wolf will effectively have a passive perception of 18 when advantage is applied.
To continue with your example. Assuming the rogue rolled 19+ with their stealth then none of the opponents would notice him. The fighter rolled a 13 stealth which allows the wolf to notice them but not Klarg or the goblins then the Wolf is NOT surprised and will take its first turn normally. Let's say the cleric rolled a 10 for stealth (which is the only number where Klarg would notice them but the goblins wouldn't). In this case, both the wolf and Klarg notice the cleric. This means that Klarg is not surprised because he also noticed a threat. This all assumes that the characters can't be seen or that the DM ruled that none of the creatures were looking in the direction of the characters so that they are unseen. It is not possible to hide if you can be seen.
The only creatures surprised are the goblins because they did not notice a threat.
Any creatures that are surprised can not take reactions until after their first turn and can take no actions on their first turn. Essentially, they lose a turn.
You would then roll initiative.
However, it is important to keep track of which characters are still hidden and from whom. If they are hidden behind something so they are unseen then the rules for Unseen Attackers apply to the first attack they would make from where they are hidden (usually ranged attacks only since if the character steps out and walks towards a creature they are usually seen and are no longer hidden). An Unseen Attacker would have advantage on their first attack roll. Rogues tend to make use of this feature frequently. So in this case, the rogue would have advantage on a ranged attack against all the targets present (as long as they are still unseen on their turn) if the attack is made by just stepping from behind whatever cover they are using to hide. The fighter would have advantage against Klarg and the goblins. The cleric would have advantage against only the goblins.
"Unseen Attackers and Targets
Combatants often try to escape their foes’ notice by hiding, casting the invisibility spell, or lurking in darkness.
When you attack a target that you can’t see, you have disadvantage on the attack roll. This is true whether you’re guessing the target’s location or you’re targeting a creature you can hear but not see. If the target isn’t in the location you targeted, you automatically miss, but the DM typically just says that the attack missed, not whether you guessed the target’s location correctly.
When a creature can’t see you, you have advantage on attack rolls against it.
If you are hidden — both unseen and unheard — when you make an attack, you give away your location when the attack hits or misses."
----------------
So the stealth check at the beginning of combat has two purposes. Determine surprise and if the character is behind something they can hide behind then determine who is hidden. If the characters were sneaking up a corridor or through a cave when they are noticed they may not have any cover in which case the stealth roll determines surprise but since the characters can be seen clearly, none of them are hidden.
----------------
More answers :)
1) You use passive perception to avoid rolling too many dice. Passive perception represents the character or creature actively looking around for threats. If the character or creature is asleep, working on something else, concentrating on reading a book or some other activity then the character/creature may not have any passive perception at all. In this case, the passive perception is used because the creatures ARE looking around and are aware of their environment. If they were sleeping, there would be no check unless the DM decided there was a chance for the characters to be so noisy they would wake the creatures up. The default assumption for both players and NPCs is that if they aren't doing something else then they are aware of their environment. A DM could apply circumstantial modifiers if they like. A sleepy guard for example might have disadvantage on their perception checks which would give -5 to their passive perception.
From chapter 8:
"Noticing Threats
Use the passive Wisdom (Perception) scores of the characters to determine whether anyone in the group notices a hidden threat. The DM might decide that a threat can be noticed only by characters in a particular rank. For example, as the characters are exploring a maze of tunnels, the DM might decide that only those characters in the back rank have a chance to hear or spot a stealthy creature following the group, while characters in the front and middle ranks cannot.
While traveling at a fast pace, characters take a –5 penalty to their passive Wisdom (Perception) scores to notice hidden threats.
Encountering Creatures. If the DM determines that the adventurers encounter other creatures while they’re traveling, it’s up to both groups to decide what happens next. Either group might decide to attack, initiate a conversation, run away, or wait to see what the other group does.
Surprising Foes. If the adventurers encounter a hostile creature or group, the DM determines whether the adventurers or their foes might be surprised when combat erupts. See chapter 9 for more about surprise.
Other Activities
Characters who turn their attention to other tasks as the group travels are not focused on watching for danger. These characters don’t contribute their passive Wisdom (Perception) scores to the group’s chance of noticing hidden threats. However, a character not watching for danger can do one of the following activities instead, or some other activity with the DM’s permission."
Characters or creatures that are involved in doing something else don't contribute their passive perception for noticing hidden threats.
It is important to remember that in 5e "passive" checks do not refer to the character or creature doing nothing. It refers to the character or creature NOT rolling dice. Basically, the player is being passive because they don't roll a die - it isn't the character being passive. Similarly, an active check is one where the die is rolled, not one where the character/creature necessarily takes a particular action. Passive checks can be applied to any skill check.
"Passive Checks
A passive check is a special kind of ability check that doesn’t involve any die rolls. Such a check can represent the average result for a task done repeatedly, such as searching for secret doors over and over again, or can be used when the DM wants to secretly determine whether the characters succeed at something without rolling dice, such as noticing a hidden monster."
2) Surprise is a property that a creature has in combat if they notice no threats. If they notice ANY threat, they are not surprised even if they didn't notice some threats. All surprise does is cause the surprised creature to take no actions on their first turn. It does not give attackers advantage or any other benefits.
"If you’re surprised, you can’t move or take an action on your first turn of the combat, and you can’t take a reaction until that turn ends. A member of a group can be surprised even if the other members aren’t."
In your example, only the goblins are surprised because they noticed no threats. Noticing ANY threat prevents a creature from being surprised.
3) Surprise NEVER imposes advantage. Surprise and the unseen attacker/target rules are completely separate things though they share a stealth roll in common in some cases.
A hidden creature may be considered UNSEEN and apply the rules for unseen attackers to their first attack when they first poke out from behind cover (stalagmites in your example). The benefit of being unseen only applies to the first attack if the attacker has more than one attack (e.g. from the extra attack feature). Unseen also won't usually apply if the attacker has to walk up to the target to make their attack. The target will see them coming, the attacker is no longer hidden and unseen so advantage from the Unseen Attacker rule would not apply.
Please note before the players get a chance to stealth up, THEY must make their passive perception check to notice the enemy. Unless they were going around being sneaky for no reason.
Please note before the players get a chance to stealth up, THEY must make their passive perception check to notice the enemy. Unless they were going around being sneaky for no reason.
Umm ... when invading an enemy camp in a bunch of caves (which is what Cragmaw Hideout in LMoP would be) ... then the default behaviour when an enemy could be around any corner is much more likely to be stealthy than not. Personally, I wouldn't call that "no reason".
In addition, since the travel rules allow for entire parties to travel stealthily without having first identified something to be stealthy about, I would say that, in general, there is no requirement to be aware of something to hide from before choosing to hide.
An enemy camp in a bunch of caves has just as much reason to have guards on active duty, making active perception checks every round as the players have to be stealthy.
The basic assumption that the players are on guard/stealthy while the enemy is not is heavily flawed.
If you want to play the monsters as morons, go ahead. But no bunch of players is going to sneak up on a bunch of Kobolds famous for building traps.
An enemy camp in a bunch of caves has just as much reason to have guards on active duty, making active perception checks every round as the players have to be stealthy.
The basic assumption that the players are on guard/stealthy while the enemy is not is heavily flawed.
If you want to play the monsters as morons, go ahead. But no bunch of players is going to sneak up on a bunch of Kobolds famous for building traps.
Guards that are on duty and actively looking for trouble can use their active perception skill. The rest of the inhabitants of a camp typically will not be, because they're busy eating, divvying up loot from their last raid, taking care of business in the bushes, sleeping, or doing whatever else they do when they're at home. I mean, have you ever been to a military base? Even in a war zone, every soldier is not on alert all the time- that's just not possible to maintain, and most enemy monsters are significantly less disciplined than that.
Rollback Post to RevisionRollBack
Find your own truth, choose your enemies carefully, and never deal with a dragon.
"Canon" is what's factual to D&D lore. "Cannon" is what you're going to be shot with if you keep getting the word wrong.
From what I can only assume is the fact that the OP of the thread is using the pregen chars, and somehow managed to get to the main event without alerting the nest.
First strikes against an unaware enemy are one thing, walking into your own trap is a lesson. I usally enforce the never assume you were never noticed rule, keeps players on their toes.
Generally, it's harder to be surprised by a group of creatures than a lone one since as soon as you perceive one of them, you aren't surprised. And It's even more hard when a wolf,is present.
If as DM you want to reward the party's effort and think it'd be fun, you can always still determine surprise regardless of dice rolls since afterall ''The DM determines who might be surprised.''
But if you go by the book and no enemy end up surprised, party members might still be unseen and have advantage to attack them depending on what conditions allowed them to use Stealth.
In the scenario you presented, it also depends if the enemies were warned or not. If they weren't the characters have a good chance to surprise them. This could mean they have advantage to the Dexterity (Stealth) check for exemple.
Developments
If Klarg is warned by the goblins in area 7 that the hideout is under attack, he and his wolf hide behind stalagmites while the goblins take cover behind the piles of supplies, hoping to ambush the characters when they enter the cave.
If Klarg and company are not warned about possible attackers, the characters have a good chance to surprise them. The easiest way for the characters to achieve this is to climb the chimney from area 3, since Klarg does not expect an attack from that direction.
In 3.5e there was a cool thing called a sneak attack round were the sneaking party got 1 round to attack or something like that im not sure if it was 3.5e but it was very cool
dear god i feel old saying 3.5E
Edit:This feature is kinda in 5E but it works more as a effect nowadays
Hi guys. New aspiring DM here. Our group just ran very first session, which went well but also left my head slightly spinning. Even after hours of prep, I still have questions. Figure I’ll start with a simple one here.
How do I handle the PC party surprising a group of different monsters? I guess I should mention potential spoiler alert in next paragraph.
Specifically, we’re playing the Phandelver module and the PC group successfully climbed up the fissure into Klarg’s chamber. The party and opposing monsters have the following stats:
- Rogue = Stealth +7
- Fighter = Stealth +3
- Cleric = Stealth -1
- Klarg = Perception +0 (WIS 10)
- Ripper = Perception +3 (WIS 13) + Advantage on Perception checks (Keen Hearing and Smell ability)
- Goblins = Perception -1 (WIS 9)
Per the Surprise section in the DnD 5e Starter Rulebook: The DM compares the Dexterity (Stealth) checks of anyone hiding with the passive Wisdom (Perception) score of each creature on the opposing side. Any character or monster that doesn’t notice a threat is surprised at the start of the encounter.
This raises the following questions:
1) To determine surprise in this case, it seems I need to have each party member roll a Stealth check and compare to the monster’s static Perception stat. This assumes the monsters were not actively scanning for any threats, so it's passive rather than having each monster roll a Perception check. Is that correct?
2) To continue, let’s say the Rogue’s Stealth check is successful against all three monsters; but the Fighter only succeeds against Klarg and the goblins; and the Cleric only succeeds against the goblins. Does the Rogue automatically impose surprise on all three monsters? Or can each PC only attack with surprise against each respective creature they successfully rolled Stealth against?
3) How do I determine when surprise imposes Advantage? I understand that a combatant gains advantage if they attack from being unseen/hidden. So if the PCs party pops out from behind stalagmites to shoot their bows, isn’t that just like being unseen? Doesn’t the whole point of surprise indicate the ambushers were undetected, and therefore were not seen?
I believe it’s very easy to overthink these rules. I’d appreciate if you guys can help set me straight for next time. Many thanks in advance.
First issue is the wolf Ripper, that advantage to perception is a difficulty that might alert the enemy’s to your approach.
In this instance I would make it simple, group stealth vs group perception. Trying to figure out individual who surprised who is easy, if all three of your PC’s individual stealth roll beat the roll or passive perception of the enemy ( whichever is greater ) that opponent is fully surprised and suffers the condition. If only one or two PC’s beat an enemy, then that opponent rolls initiative at disadvantage, because they weren’t expecting it but still had time to react.
Now that is just my take on the situation in vacuum, and others will play it differently. It’s really up to the DM to decide just how difficult it will be for the group to get a jump on Klarg.
Surprise is a bit all or nothing in many cases.
The key line is "Any character or monster that doesn’t notice a threat is surprised at the start of the encounter."
A creature is surprised only if they don't notice any threat. If they notice some but not all of the threats then they are on the alert and are not surprised even if there are creatures that they did not notice.
In your example, you have three enemies.
Klarg has a 10 passive perception.
The goblins have a 9 passive perception.
Ripper has proficiency in the perception skill giving a +3 and base passive perception of 13. However, they have advantage on perception checks involving hearing or smell. Advantage on a skill adds +5 to a passive check value. In this case, if the wolf is likely to smell or hear the characters than see them (which is probably the case) then the wolf will effectively have a passive perception of 18 when advantage is applied.
To continue with your example. Assuming the rogue rolled 19+ with their stealth then none of the opponents would notice him. The fighter rolled a 13 stealth which allows the wolf to notice them but not Klarg or the goblins then the Wolf is NOT surprised and will take its first turn normally. Let's say the cleric rolled a 10 for stealth (which is the only number where Klarg would notice them but the goblins wouldn't). In this case, both the wolf and Klarg notice the cleric. This means that Klarg is not surprised because he also noticed a threat. This all assumes that the characters can't be seen or that the DM ruled that none of the creatures were looking in the direction of the characters so that they are unseen. It is not possible to hide if you can be seen.
The only creatures surprised are the goblins because they did not notice a threat.
Any creatures that are surprised can not take reactions until after their first turn and can take no actions on their first turn. Essentially, they lose a turn.
You would then roll initiative.
However, it is important to keep track of which characters are still hidden and from whom. If they are hidden behind something so they are unseen then the rules for Unseen Attackers apply to the first attack they would make from where they are hidden (usually ranged attacks only since if the character steps out and walks towards a creature they are usually seen and are no longer hidden). An Unseen Attacker would have advantage on their first attack roll. Rogues tend to make use of this feature frequently. So in this case, the rogue would have advantage on a ranged attack against all the targets present (as long as they are still unseen on their turn) if the attack is made by just stepping from behind whatever cover they are using to hide. The fighter would have advantage against Klarg and the goblins. The cleric would have advantage against only the goblins.
"Unseen Attackers and Targets
Combatants often try to escape their foes’ notice by hiding, casting the invisibility spell, or lurking in darkness.
When you attack a target that you can’t see, you have disadvantage on the attack roll. This is true whether you’re guessing the target’s location or you’re targeting a creature you can hear but not see. If the target isn’t in the location you targeted, you automatically miss, but the DM typically just says that the attack missed, not whether you guessed the target’s location correctly.
When a creature can’t see you, you have advantage on attack rolls against it.
If you are hidden — both unseen and unheard — when you make an attack, you give away your location when the attack hits or misses."
----------------
So the stealth check at the beginning of combat has two purposes. Determine surprise and if the character is behind something they can hide behind then determine who is hidden. If the characters were sneaking up a corridor or through a cave when they are noticed they may not have any cover in which case the stealth roll determines surprise but since the characters can be seen clearly, none of them are hidden.
----------------
More answers :)
1) You use passive perception to avoid rolling too many dice. Passive perception represents the character or creature actively looking around for threats. If the character or creature is asleep, working on something else, concentrating on reading a book or some other activity then the character/creature may not have any passive perception at all. In this case, the passive perception is used because the creatures ARE looking around and are aware of their environment. If they were sleeping, there would be no check unless the DM decided there was a chance for the characters to be so noisy they would wake the creatures up. The default assumption for both players and NPCs is that if they aren't doing something else then they are aware of their environment. A DM could apply circumstantial modifiers if they like. A sleepy guard for example might have disadvantage on their perception checks which would give -5 to their passive perception.
From chapter 8:
"Noticing Threats
Use the passive Wisdom (Perception) scores of the characters to determine whether anyone in the group notices a hidden threat. The DM might decide that a threat can be noticed only by characters in a particular rank. For example, as the characters are exploring a maze of tunnels, the DM might decide that only those characters in the back rank have a chance to hear or spot a stealthy creature following the group, while characters in the front and middle ranks cannot.
While traveling at a fast pace, characters take a –5 penalty to their passive Wisdom (Perception) scores to notice hidden threats.
Encountering Creatures. If the DM determines that the adventurers encounter other creatures while they’re traveling, it’s up to both groups to decide what happens next. Either group might decide to attack, initiate a conversation, run away, or wait to see what the other group does.
Surprising Foes. If the adventurers encounter a hostile creature or group, the DM determines whether the adventurers or their foes might be surprised when combat erupts. See chapter 9 for more about surprise.
Other Activities
Characters who turn their attention to other tasks as the group travels are not focused on watching for danger. These characters don’t contribute their passive Wisdom (Perception) scores to the group’s chance of noticing hidden threats. However, a character not watching for danger can do one of the following activities instead, or some other activity with the DM’s permission."
Characters or creatures that are involved in doing something else don't contribute their passive perception for noticing hidden threats.
It is important to remember that in 5e "passive" checks do not refer to the character or creature doing nothing. It refers to the character or creature NOT rolling dice. Basically, the player is being passive because they don't roll a die - it isn't the character being passive. Similarly, an active check is one where the die is rolled, not one where the character/creature necessarily takes a particular action. Passive checks can be applied to any skill check.
"Passive Checks
A passive check is a special kind of ability check that doesn’t involve any die rolls. Such a check can represent the average result for a task done repeatedly, such as searching for secret doors over and over again, or can be used when the DM wants to secretly determine whether the characters succeed at something without rolling dice, such as noticing a hidden monster."
2) Surprise is a property that a creature has in combat if they notice no threats. If they notice ANY threat, they are not surprised even if they didn't notice some threats. All surprise does is cause the surprised creature to take no actions on their first turn. It does not give attackers advantage or any other benefits.
"If you’re surprised, you can’t move or take an action on your first turn of the combat, and you can’t take a reaction until that turn ends. A member of a group can be surprised even if the other members aren’t."
In your example, only the goblins are surprised because they noticed no threats. Noticing ANY threat prevents a creature from being surprised.
3) Surprise NEVER imposes advantage. Surprise and the unseen attacker/target rules are completely separate things though they share a stealth roll in common in some cases.
A hidden creature may be considered UNSEEN and apply the rules for unseen attackers to their first attack when they first poke out from behind cover (stalagmites in your example). The benefit of being unseen only applies to the first attack if the attacker has more than one attack (e.g. from the extra attack feature). Unseen also won't usually apply if the attacker has to walk up to the target to make their attack. The target will see them coming, the attacker is no longer hidden and unseen so advantage from the Unseen Attacker rule would not apply.
Please note before the players get a chance to stealth up, THEY must make their passive perception check to notice the enemy. Unless they were going around being sneaky for no reason.
Umm ... when invading an enemy camp in a bunch of caves (which is what Cragmaw Hideout in LMoP would be) ... then the default behaviour when an enemy could be around any corner is much more likely to be stealthy than not. Personally, I wouldn't call that "no reason".
In addition, since the travel rules allow for entire parties to travel stealthily without having first identified something to be stealthy about, I would say that, in general, there is no requirement to be aware of something to hide from before choosing to hide.
An enemy camp in a bunch of caves has just as much reason to have guards on active duty, making active perception checks every round as the players have to be stealthy.
The basic assumption that the players are on guard/stealthy while the enemy is not is heavily flawed.
If you want to play the monsters as morons, go ahead. But no bunch of players is going to sneak up on a bunch of Kobolds famous for building traps.
Guards that are on duty and actively looking for trouble can use their active perception skill. The rest of the inhabitants of a camp typically will not be, because they're busy eating, divvying up loot from their last raid, taking care of business in the bushes, sleeping, or doing whatever else they do when they're at home. I mean, have you ever been to a military base? Even in a war zone, every soldier is not on alert all the time- that's just not possible to maintain, and most enemy monsters are significantly less disciplined than that.
Find your own truth, choose your enemies carefully, and never deal with a dragon.
"Canon" is what's factual to D&D lore. "Cannon" is what you're going to be shot with if you keep getting the word wrong.
From what I can only assume is the fact that the OP of the thread is using the pregen chars, and somehow managed to get to the main event without alerting the nest.
First strikes against an unaware enemy are one thing, walking into your own trap is a lesson. I usally enforce the never assume you were never noticed rule, keeps players on their toes.
Generally, it's harder to be surprised by a group of creatures than a lone one since as soon as you perceive one of them, you aren't surprised. And It's even more hard when a wolf,is present.
If as DM you want to reward the party's effort and think it'd be fun, you can always still determine surprise regardless of dice rolls since afterall ''The DM determines who might be surprised.''
But if you go by the book and no enemy end up surprised, party members might still be unseen and have advantage to attack them depending on what conditions allowed them to use Stealth.
In the scenario you presented, it also depends if the enemies were warned or not. If they weren't the characters have a good chance to surprise them. This could mean they have advantage to the Dexterity (Stealth) check for exemple.
In 3.5e there was a cool thing called a sneak attack round were the sneaking party got 1 round to attack or something like that
im not sure if it was 3.5e but it was very cool
dear god i feel old saying 3.5E
Edit:This feature is kinda in 5E but it works more as a effect nowadays