As a DM, you have the authority to set DCs and other things and the game was designed expecting you to use this responsibility:
Many unexpected things can happen in a D&D campaign, and no set of rules could reasonably account for every contingency. […] The direction we chose for the current edition was to lay a foundation of rules that a DM ...
Just give advantage
I’ll get to the math in a minute, but the math really should be moot: there is no guidance for altering DCs based on PC actions because the point of the advantage mechanic is to eliminate the hundreds of ways of tweaking situational probability.
Advantage (and disadvantage) exist entirely to handle exactly these sorts of situations. ...
Mechanically, I would say the main difference is that advantage is easier and provides more stable results (As your result chances go from evenly distributed, to a favorably skewed curve). 5e favors using advantage/disadvantage as a quick, simple, effective way to deal with temporary bonuses.
Narratively, advantage is a temporary bonus to one action, while ...
This is answered on page 7 of the PHB:
3. Compare the total to a target number. If the total equals or exceeds the target number, the ability check, attack roll, or saving throw is a success. Otherwise, it’s a failure. [...] The target number for an ability check or a saving throw is called a Difficulty Class (DC).
And on page 174:
If the total ...
Advantage is the usual way
DnD 5e seldom uses situational modifiers to rolls. Advantage is the usual way for the system to describe something is particularly easy because of some circumstance. Advantage is more conventional than lowering the DC, and your players are more likely to be used to it than changing modifiers or DCs.
Advantage is more transparent
Dungeon Master Guide calls this Degrees of Failure or Success at a Cost
The opening paragraph of the Resolution and Consequences section of the DMG (p. 243) encourages non binary results to player actions:
As a DM, you have a variety of flourishes and approaches you can take when adjudicating success and failure to make things a little less black-and-...
From p. 237 of the Dungeon Master's Guide, under the "Using Ability Scores" header:
When a player wants to do something, it’s often appropriate to let the attempt succeed without a roll or a reference to the character’s ability scores. For example, a character doesn’t normally need to make a Dexterity check to walk across an empty room or a Charisma check ...
Jonathan Tweet invented 3e’s core mechanic and its DC concept
Difficulty Class did indeed make its D&D debut in 3e,1 and has been traced by Shannon Appelcline's historical work directly to Jonathan Tweet, lead designer of Dungeons & Dragons 3rd Edition.
Initial 3e work began without a design vision shortly after WotC acquired TSR, and CEO Peter ...
Cleric's Spell Save DC
You are correct that RAW the saving DC is not specified. I have been unable to find any source that officially corrects this oversight. However, I think using the cleric's spell save DC is a fairly safe assumption.
Most cleric features that require a save come under the Channel Divinity set of features. In the text for that feature ...
You probably use your own spell save DC, but RAW is unclear
The description of the Ring of Shooting Stars (DMG, p. 192) does indeed not give a spell save DC for faerie fire. It also gives access to dancing lights and light, the latter of which may also require a spell save DC ("if you target an object held or worn by a hostile creature"), which the item's ...
There's no "DC" for either of those, any more than there's a DC for killing an enemy in combat with a sword.
Instead, there's grapple checks (like AC) and damage rolls that progress toward death or unconsciousness (depending on non-lethal vs lethal damage).
If your players are asking for a homebrew save-or-die in grappling, tell them there is absolutely no ...
Don't bother yourself with rolls for such things. The PCs are not hiding, the bandits have sentries, then they would automatically spot the PCs.
Next time, the PCs may think about hiding... Right now they are obvious as heck.
Putting it a different way would your PCs scream and moan if the situation was reversed? (Mine would).
Now if you want to know ...
The DC for Channel Divinity abilities is described in the main description for your Sacred Oaths, in your list of class features. Specifically, it's:
Some Channel Divinity effects require saving throws. When you use such an effect from this class, the DC equals your paladin spell save DC.
You can find this (and some other general information about how ...
The Monster Manual entry for the Drow states under Innate Spellcasting (emphasis mine):
The drow’s spellcasting ability is Charisma (spell save DC 11). It can innately cast the following spells, requiring no material components.
Generally, the spell save DC will be listed in a similar section for all monsters with Innate Spellcasting.
I believe your best option would be to model the effects of the room off of one of the Heat Metal Spells from one of the older editions of Dungeons and Dragons.
The way the spells are engineered, the longer your victims remain in the room, the more pentalties, and eventually damage they suffer.
Perhaps an increasing DC Constitution saving throw against the ...
Sometimes the Rules Are Guidelines...
According to the Player's Handbook, "[Y]ou can use [Knowledge skills] to identify monsters and their special powers or vulnerabilities. In general, the DC of such a check equals 10 + the monster's HD. A successful check allows you to remember a bit of useful information about that monster" (78). And there just ain't ...
Your analysis is correct (mostly).
Minor illusion is a good example of this. The text (PHB 260) says:
... the creature can determine that it is an illusion with a successful Intelligence (Investigation) check against your spell save DC.
If a creature under the control of the DM uses its action to investigate the illusion, the DM rolls the d20, adds the ...
It is the spellcaster's spell save DC
The DC to resist one of your spells equals 8 + your spellcasting ability modifier + your proficiency bonus + any special modifiers. (PHB - Saving Throws)
So the person that casts the spell sets the DC (as indicated by the term "you"/"your" which the PHB uses throughout this section to refer exclusively to the caster)....
If the zombie has resistance or vulnerability to the attack, the DC is calculated by the final damage amount.
From PhB: Resistance and Vulnerability
For example, a creature has resistance to bludgeoning damage and is hit by an attack that deals 25 bludgeoning damage. The creature is also within a magical aura that reduces all damage by 5. The 25 damage ...
Typically a spell save DC is 8 + spellcasting ability modifier + proficiency bonus (PHB p205). In the case of the Drow that would be 8 + 1 + 2 = 11.
Proficiency bonus is based on the creature's CR. There's a chart in the Monster Manual (p8) that you can use to check it.
However. I don't know what version of the Monster Manual you're reading because ...
The text you've quoted pretty much answers your own question.
Add your proficiency bonus to the beast’s AC, attack rolls, and damage rolls, as well as to any saving throws and skills it is proficient in.
A Wolf is proficient in Perception and Stealth, so you add your proficiency bonus to those. You increase the Wolf's AC of 13 by your proficiency, ...
A +29 on Intimidate is a very large bonus. Especially on a fighter, who has few skill points and little use for Charisma in most cases; almost all of that is probably from skill ranks, which implies a very high level character.
Such a person should be trivially succeeding on attempts to demoralize most anything. Anything short of an actual god should be an ...
A DC could be any (real) number you like.
The reference table shows descriptors for DCs of 10, 15, 20, &c. This is just to provide you some touchstones--you can set intermediate DCs any time you'd like.
(However, the fine-tuning by 5% probabilities that provides isn't, in my experience, that useful and increases my cognitive load more than necessary. I'...
On page 278 of the DMG, it includes this paragraph:
Alternatively, you can calculate a monster's save DC as follows: 8 + the monster's proficiency bonus + the monster's relevant ability score. You choose the ability that best applies.
For example, if the effect is a poison, the relevant ability is probably the monster's Constitution.
If you take a ...
...Actually, I think I found it after examining the hydra.
The DC formula is DC = 10 + ((Hit Dice)/2) + Stat Modifier. 10 + (7/2, rounded down = 3) + 3 = 16. That's how it's calculated.
So, the Bog Nixie, being a Nixie with the Advanced creature template, would be calculated as DC = 10 + (2/2 = 1) + 6 = 17.
...I recently read something about how ...
Yes, in the Starter Set.
In the introduction section of the Lost Mines of Phandelver there is a primer section for new DMs which includes descriptions of what type of activities would make up the Easy, Moderate, and Hard DC check levels.
Easy (DC 10). An easy task requires a minimal level of competence or a modicum of luck to accomplish.
Glad you could reverse-engineer the save DC calculation. It is actually described in the SRD - and in several other places. Kept that one as an example.
Step 8: Special Abilities and Qualities
Most special abilities that cause damage, such as breath weapons, give a save (Fortitude, Reflex, or Will depending on the ability). The DC for almost all ...
There is no rule about which is harder
DMG p. 239 says the following regarding setting the Difficulty Class (DC):
When you do so, think of how difficult a task is and then pick the associated DC from the Typical DCs table.
Very easy 5
Very hard 25
Nearly impossible 30
The numbers associated with ...
Use skill checks
It might help you to think about the steps involved with achieving the end result and how the relevant characters/creatures would react. In your situation, the end result is something like a PC standing triumphantly with one foot resting atop a hogtied zombie, Captain Morgan style.
Obviously, the zombie (to the extent that a mindless ...
The idea you're thinking of is often called degrees of success or grades of success. It's been seen in a handful of places in Dungeons & Dragons history, and stands at the base of many other game systems, such as Apocalypse World.