I was reading the Players Handbook 1 and I don't understand how the opposed check works, especially in context of a stealth check.
[RPG] How does an opposed (stealth) check work
dnd-4enew-playersskills
Related Solutions
First off, that map is infamous in my gaming group. It's from "Keep on the Shadowfell," an adventure published before even the 4e PHB. As such, it's got a lot of... quirks, and then the Stealth rules changed in the PHB2 (see Sage's link at the bottom for full details of current rules). The party is supposed to enter from the West (left) and so the kobolds are hiding on the wrong side of the bushes. There are other problems with it too, as we'll see.
I'm using the DDI Compendium glossary for reference:
- Yes, Stealth is an active check against passive Perception.
- They should not get any bonuses to Stealth checks. Total cover and superior concealment allow Stealth checks, and that's enough.
- You need total concealment or superior cover to make a Stealth check. The boulders provide superior cover, but the bushes in that encounter "are lightly obscured and provide normal cover," which means that technically the kobolds not next to rocks shouldn't be able to hide at all.
However!
Keep out of Sight: If the creature no longer has any cover or concealment from a target, it doesn’t remain hidden from the target. The creature doesn’t need superior cover, total concealment, or to stay outside line of sight, but it at least needs partial cover or partial concealment from a target to remain hidden. A hidden creature can’t use another creature as cover to remain hidden.
So once the kobolds manage to hide (somehow) then they can stay hidden by moving into squares filled with bushes.
Here's how I think it should play out: the kobolds hide before the PCs come around the bend (are placed on the map), which means they had total concealment from the PCs, allowing the Stealth checks. Then they should jump into the bushes to be able to remain hidden until the PCs are in position.
Sage's Edit: Stealth is complicated enough that it has its own stickied guide at the official 4e rules Q&A forum.
Do all opposing skill checks automatically succeed on a natural 20 ( unless there's a tie )?
No, but it's pretty hard for an opponent to beat a natural 20. The opposing roll only ever wins if its total check is higher despite the natural 20. This may happen, say, when a player has a negative modifier to a roll and the opponent rolls high and/or has high scores in the opposing roll.
In one of our games, my 8 strength Lore Bard beat our 18 strength fighter in an arm-wrestling, basically a Strength(Athletics) contest, by picking up Expertise in Athletics, throwing insults at him (Cutting Words Lore Bard feature), and cheating (casting Enhance Ability on myself).
If not all opposing skill checks automatically succeed on a natural 20, do any of them? If so, which ones?
Ability Checks don't have critical success unless house-ruled into your game but I'd be wary of this and that's another topic entirely.
Besides saves & attack rolls, what treats a natural 20 as an automatic success?
Only Attack Rolls treats a natural 20 as a critical hit, even if you roll a natural 20 on a Wisdom Saving Throw, you're still going to be frightened of that dragon if the total doesn't equal or surpass the Save DC.
Best Answer
Let's go step by step.
Opposed roll vs. Passive DC
In D&D 4E, not all skill checks will be opposed to another skill check. In some circumstances a skill check can be made against a Passive DC. Only Perception and Insight have a passive DC.
A simple example is when a character is doing something else. Fighting, reading a book, sleeping etc. If a character doesn't declare he's looking for something or actively listening, assume he's using Passive Perception. Same for Insight.
Notice there are no Passive Stealth or Climb. This is how I understood when to use passive vs. opposed roll. An "active" skill check requires your full attention and awareness.
Usually an NPC that will sneak on a player or try to lie will always target the Passive skill DC unless the player mention he's actively paying attention.
As a DM, if you believe that your NPC would have a reason to be actively searching (Perception) or paying close attentions to your words and gesticulation (Insight) then use the Opposed check method.
In any other situation, assume Passive DC.