I'm a little bit confused about skill checking. I'm reading through LMoP and in the first goblin encounter, the adventure suggest the goblins make stealth check against PCs passive perception.
Then later, I'm reading about the nothic encounter from which I understand the creature can be intimidated or persuaded to cooperate or tell what it knows. For this, players would have to make persuasion/intimidation check. But this is where I'm a bit confused – players make skill checks agains what? DC set by a DM? Or nothic makes a charisma saving throw when someone tries to persuade it? Or is it DC simply because nothic "doesn't know in advance" they're trying to persuade it so it can't make a saving throw against it?
I simply don't understand why with stealth there's a contest stealth/passive perseption and persuasion should simply be against DC set by a DM?
Thanks for any answers!
Best Answer
Don't overthink this
Breathe easy - you cannot do this wrong. Some DMs will favor ability checks over contests and some will lean more heavily on passive over active checks: each of these DMs is playing the game by the rules because "the DM decides what happens".
How to Play
First of all, focus on the fundamental rule of D&D 5e:
Note that rolling an ability check is never a requirement. In general, ability checks are only called for where:
Ability Checks versus Contests
Page 174 of the Player's Handbook calls out the distinction between an ability check which is made against a DC set by the DM and contest where each creature makes an opposed ability check.
Ability Check
Contest
It is worth noting that the outcomes of contests are more random since they involve at least 2 rolls (more if advantage/disadvantage).
Passive Checks
In addition to that, p. 175 introduces the idea of a passive check:
The goblins
The author is suggesting:
A contest: the characters' Wisdom (Perception) is being opposed by the goblins' Dexterity (Stealth).
A passive check: presumably because this is specifically the example given as to when these are appropriate, "noticing a hidden monster".
Equivalently, the DM could call for the players to make an active Wisdom (Perception) check and use the Goblins' passive Dexterity (Stealth): this is mechanically equivalent. Note that an active vs active check is not mechanically equivalent - an active check improves the characters' chances by 2.5%.
The advantages of the author's suggestion are:
The nothic
Is a roll called for? If the characters offer the nothic what it wants at trivial cost why would you roll? Other than the fact that the damn thing is insane and you may want to model this with randomness.
What you should determine is if this is a contest or not. It becomes a contest when "one character’s or monster’s efforts are directly opposed to another’s". In a negotiation this is not, or not necessarily, the case. If you decide that it is a contest then a Charisma (Persuasion) by the character is opposed by a Wisdom (Insight) by the nothic with advantages/disadvantages applied depending on the inclination of the nothic to do what they want anyway. If you decide that it isn't then just set a difficulty representing how hard it is to persuade and insane creature to do whatever is being asked.
Passive checks are inappropriate here.
Generalizing
Don't roll unless you have to.
A contest is appropriate when there is active opposition and the skill of the opponent is relevant to the outcome. For example a Charisma (Deception) check is more likely to be a contest then a Charisma (Persuasion) check.
Passive checks are appropriate where a creature is not actively engaged.
If there is a passive check and an active check it is irrelevant which is which. An active Dexterity (Stealth) check vs a passive Wisdom (Perception) is exactly the same as a passive Dexterity (Stealth) check vs an active Wisdom (Perception). This allows you to let the most appropriate person roll the dice: the DM if you are keeping secrets or the players if you want them more engaged in the outcome.