How does nondetection interact with School of Divination's Portent?

Question

As the title suggests, me and some friends had a disussion on this. First, here is the RAW from PHB on Portent (PHB 116):

Starting at 2nd leel when you choose this school, glimpses of the future begin to press in on your awareness. When you finish a long rest, roll two d20s and record the numbers rolled. You can replace any attack roll, saving throw, or ability check made by you or a creature that you can see with one of these foretelling rolls. You must choose to do so before the roll, and you can replace a roll in this way only once per turn. Each foretelling roll can be used only once. When you finish a long rest, you lose any unused foretelling rolls.

And the spell description of nondetection (PHB 263):

For the duration, you hide a target that you touch from divination magic. The target can be a willing creature or a place or an object no larger than 10 feet in any dimension. The target can't be targeted by any divination magic or perceived through magical scrying sensors.

Now let's say, to make this a little easier to decide, instead of casting nondetection which has a duration the target is simply wearing an Amulet of Proof Against Detection and Location which has exactly the same description(DMG 150):

While wearing this amulet, you are hidden from divination magic. You can't be targeted by such magic or perceived through magical scrying sensors.

Now we can eliminate the "When did the wizard actually see this person in a vision and did he have nondetection up at that time" topic.

The main thing my friend insisted on was that "Portent isn't tagged as divination magic.", "It's not a spell." or my favourite "It's not magic, it's precognition." Lastly, he gave this example in Portent's favor:

A thief wearing the amulet tries to steal a cup. Now the diviner can use portent to affect the thief's roll because he can see the cup doesn't go anywhere or the cup won't be there in couple seconds.

I believe if there is a nondetectable target in the area the whole thing is supposed to be fuzzy and the amulet should cover anything that target interacts with for some time. We had a lot of different opinions on how things were supposed to be but you get the idea.

What's the final verdict?

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Before continuing i want to say this didn't happen in a game or anything, just a random thought while reading the abilities, in a game i'd probably let ignore the divination magic part in some cases for player favor as you suggested. But as a general rule i want to keep asking the things that just don't click.

"Speaking purely Rules As Written, Portent is a class ability for Wizards who choose the Divination School, but it isn't classified under Divination Magic."

Then what is it? it's definitely not precognition since you are supposed to see the events during your rest. Psychics are way out of question here as well.

Whether it's a class feature or ability, there is no doubt there is magic involved in Portent and it's quite visibly placed under the School of Divination. The way i see it, it is Divination Magic in RAW. Not a spell obviously, that's why the nondetection description says magic and not spell.

"However, I would take it under advisement that the Portent isn't just targeting the creature under Nondetection, but it is also targeting the interaction."

You can replace any attack roll, saving throw, or ability check made by you or a creature that you can see with one of these foretelling rolls.

You still have to be able to target the creature before you even think about the roll.

"Let's say that the wizard has cost Hold Person on someone under Nondetection and plans to use their Portent on the saving throw. Is it that the Wizard has seen the outcome of their Spell or that they've seen the outcome of the effect on the target? It could be read either way."

I think this example is a bit flawed since there is no roll for casting the spell, only the outcome of it on the target.

Sometimes the mechanic and the game logic has to be kept separate. I believe in this case both work on the favor of nondetection. Let me explain:

Mechanic:

• Portent is Divination Magic(back to that point are we)

• Nondetection says you can't be targeted by Divination Magic

• Portent needs a target.

Logic:

• With portent you get glimpses of the future during your long rest. If there is someone protected you simply don't see — not just them but also — their effects on the environment. It's safe to say the hidden person's interactions are also hidden.

Since players can't really see the future they might learn the target is protected when they try to use Portent, saying they saw what happened. I'm thinking the DM would say somewhere along the lines of "This person wasn't in your visions", "That dagger wasn't stuck in your friend but now it is, enemy must've found a way around your divination magic" and you'd keep the Portent charge.

Answer 1

Rules as written, it is left to DM or the table for interpretation

Rules as written what you're supposed to do is look at Nondetection and Portent and decide for your table how it works. You're supposed to look at what the intent of Nondetection and the intent of Portent is supposed to be, which means you'll have to read and decide for yourself based on how you understand the rules and what works best for the fun and enjoyment of your table. That is 5e's rules philosophy.

I don't buy the "It doesn't say it is or it isn't, therefore it isn't." You can just as easily say, "It doesn't say it is or it isn't, therefore it is." Lack of evidence doesn't prove anything. The game rules do not claim to be comprehensive, and this is the natural consequence of that. This is the entire point the "rulings not rules" idiom is making. There is no burden of proof on Portent or Nondetection or the PHB as a whole to provide an answer. While that line of reasoning was implicit to 3e and 4e -- both editions that sought comprehensive and complete rules sets -- 5e actively does not do that. 5e D&D is often intentionally vague so as to leave rules open for interpretation and the system intentionally doesn't use keywords or raw mechanics. It does this so that players and DMs have the explicit freedom to interpret the rules for themselves and do what makes sense for that interaction. The designers know they can't possibly foresee every interaction in the rules, so they no longer try.

There is no clear answer by design. Yes, this means that asking, "What is RAW?" on RPG SE for 5e D&D is often a pointless exercise because the answer you should often get is, "RAW it depends on your table." This is why there are so many conflicting answers on RPG SE for 5e questions and why Sage Advice contradicts itself so often.

The rules are less important than the game. What Mearls and Crawford want is for players and DMs to stop asking WotC how to play and just make a decisions and play for themselves. If you make a mistake, admit it and make a correction. It's no less destructive than doing nothing until WotC makes a decision and then maybe changes their mind later.

You're expected to look at whole picture that the rules are giving you and to make a judgement call on what feels the most consistent and correct for your table. Is it reasonable for Nondetection to block Portent? Sure, it almost certainly is divination magic given that it's an ability of the Diviner subclass. How about a Ranger's Primeval Awareness? Well, that works like a spell, even consuming a spell slot, and it would have to be divination magic given the distance, so sure. How about a Paladin's Divine Sense? Hm... possibly, it's pretty close to Detect Good and Evil, but it's really described as the Paladin's senses. A Warlock's Devil's Sight? Hrm, hard to say. It's got elements that only True Seeing can accomplish, and Nondetection probably blocks True Seeing, but it's basically an improved Darkvision spell and that's not even Divination. So maybe partially? A Barbarian's Feral Instinct? Eh, that doesn't seem right, it's not magical. A Rogue's Blindsense? Yeah, probably not unless Blindsense is supposed to be magical, but I don't get that impression.

Answer 2

Nondetection has no RAW effect on Portent

As you've quoted above, items under Nondetection are immune from Divination magic. Speaking purely Rules As Written, Portent is a class ability for Wizards who choose the Divination School, but it isn't classified under Divination Magic. In addition, Portent is more of a 'metagaming' ability like Lucky or Halfling Luck that occurs as part of the Roll Play part of the game and not really part of the Role Play.

But there is a case for it to be Table Ruled to effect it

Given that the portent ability is for Divination wizards, I think there is a strong case for saying that someone under Nondetection wouldn't be a viable target for Portent. However, I would take it under advisement that the Portent isn't just targeting the creature under Nondetection, but it is also targeting the interaction.

An Example

Let's say that the wizard has cost Hold Person on someone under Nondetection and plans to use their Portent on the saving throw. Is it that the Wizard has seen the outcome of their Spell or that they've seen the outcome of the effect on the target? It could be read either way.

Conclusion

Given the primary logic of it not actually being in the Divination School combined with an unclear understanding of how the Portent Ability works, I think you need to generally find in favor of your PCs. Divination Wizards only get to use this 2x/day - let them shine with their class ability. Even if you allow it both ways, it's much more likely to be used against your Wizard then it is your players against an enemy.

Answer 3

Nondetection does not block Portent.

Non detection states:

The target can’t be targeted by any divination magic or perceived through magical scrying sensors.

Emphasis mine.

Therefor, we must determine if Portent is magical, and if it is magical, if it is specifically divination magic. Fortunately, the Sage Advice Compendium published by Wizards of the Coast gives us very simple questions to determine if a game ability is magical. It is a series of 5 questions:

Is it a magic item?

Is it a spell? Or does it let you create the effects of a spell that’s mentioned in its description?

Is it a spell attack?

Is it fueled by the use of spell slots?

Does its description say it’s magical?

Going through these one by one, we can assure ourselves whether Portent is a magical ability.

1. Is it a magic item? No. it is a class ability.
2. Is it a spell? Or does it let you create the effects of a spell that’s mentioned in its description? No, it is not a spell, and there is no spell mentioned in the description.
3. Is it a spell attack? No, it's not even an attack.
4. Is it fueled by the use of spell slots? No, it does not use the spell economy and is regained after a long rest.
5. Does its description say it’s magical? The words "magic" and "magical" do not appear in the description of the ability

Since it has failed all five questions and is not magical, the question of whether it is specifically divination magic becomes superfluous.

Portent is part of what WotC calls "the background magic that is part of the D&D multiverse’s physics and the physiology of many D&D creatures", the sort of thing that explains how dragons can fly or giants stand up.

Magic, as a game effect, is described as "the concentrated magical energy that is contained in a magic item or channeled to create a spell or other focused magical effect."

All quotes from the same cited document above.

So to reiterate: No, Portent, not being a specifically magical ability, is not blocked by spells or effects that block divination magic.

Answer 4

There is no interaction between portent and nondetection.

All the things your player said are correct: portent is not technically divination magic, it's not a spell, and it's precognition. Nondetection only works on divination magic, and not other means of detection, such as mundane eyeballs.

I think both of you are missing a key clause (emphasis added):

You can replace any attack roll, saving throw, or ability check made by you or a creature that you can see with one of these foretelling rolls.

If your thief is only using nondetection, he is still visible normally, and so the diviner is able to see the thieving attempt and portend its outcome. If your thief is invisible, then the diviner cannot see the thief and thus cannot use portent, even if the diviner can see the cup floating away and vanishing.

Answer 5

From what i could find (or couldn't find) the RAW does not limit Magic in any way (i.e. only spells are magic). Therefore it is not against RAW to say Portent can be Divination Magic.

Magic permeates the worlds of D&D and most often appears in the form of a spell. (PHB 201)

To see if Portent can be considered Magic (or divination magic specifically) we can check where it comes from:

Wizard Class Features (wizards love magic)

Arcane Tradition: When you reach 2nd level, you choose an arcane tradition shaping your practice of magic through one of eight schools: Abjuration, Conjuration, Divination, Enchantment...(PHB 115)

And Portent is right there under the School of Divination [Magic] (PHB 116). So Portent can be and should be classified as divination magic.

Now that we got this out of the way, the Amulet of Proof Against Detection and Location (DMG 150):

While wearing this amulet, you are hidden from divination magic. You can't be targeted by such magic or perceived through magical scrying sensors.

Since Portent requires you to have a target [that you can see] and the amulet will prevent you from targeting the wielder, we can conclude that this amulet will protect you from being affected by Portent.

Answer 6

Nondetection blocks Portent

A good reference for this question is Does Nondetection plus Invisibility hide you from the The Third Eye Wizard ability?.

Portent is clearly divination and clearly magical. The ability to have foresight is magical. Wizards are all about being magical. Nondetection protects you from divination magic. Therefore, Nondetection protects you from Portent.

Portent lets you replace a roll because you can see the effectiveness of your or some creature's actions through magical means. But you can't see any effect on a creature protected with Nondetection, so you can't apply Portent to that roll.

Because people say "it doesn't count unless its a real spell!" I'll pull my comment into my answer. Yes, Third Eye has a few abilities that have the same names as existing spells, but others do not. They are all clearly magical.

Jeremy Crawford has weighed in to say that Dispel Magic only affects spells, not all magical effects, and from that we can clearly see that there are class features that are not spells but still magical: What happens when you target a "magical effect" with Dispel Magic?.

From this we can say with certainty that, like its fellow class feature Third Eye, Portent is a magical ability and thus would be blocked by Nondetection, as unlike Dispel Magic, Nondetection works on all divination magic, not just spells.

Furthermore, if you insist on finding a spell that matches Portent to prove that it is magical, Foresight and True Strike are two such spells giving very similar effects. They give advantage instead of replacing rolls, but the concept of how the advantage is gained is very similar.