Is this Portent-like homebrew spell balanced?

Question

As a divination wizard, I love the Portent mechanic. There is little better than pointing at an ally about to unleash their biggest attack on the BBEG and telling them, 'you just rolled a 20' (or whatever number I have that's high enough for them to hit). It makes me feel like a proper divination wizard.

Unfortunately, I have found there are few combat spells that have the same feel of being able to directly influence others' fortune available. That is why I have tried to capture the feeling of Portent in spell form.

Alter Fate

2nd-level divination

Casting Time: 1 action
Range: Self
Components: V, S, M (a glass bead)
Duration: Concentration, up to 1 minute

By focusing your inner eye on the near future, you are able to influence the weave of fate. When you cast this spell, you roll 1d20 and record the number. As a reaction, you can replace any attack roll, saving throw, or ability check made by you or a creature that you can see with this foretelling roll. You must choose to do so before the roll. This foretelling roll can only be used once.

At Higher Levels: When you cast this spell using a spell slot of 3rd level or higher, you may add or subtract 1 for each spell level above 2nd to the die roll, with a minimum result of 1 and a maximum result of 20.

I am having trouble finding a proper way to estimate this spell's power level. I realize that there is a reason divination wizards only receive their third Portent die at level 14. That is why I have tried to limit the spell by requiring concentration and an action to cast.

The part I am most worried about being unbalanced is the 'at higher levels' part. Does this make it too easy to get critical hits or misses?

Presumably the adding and subtracting affect the actual d20 result? And thus you can now get crits? Also which interpretation of portent do you want us to use. Does it replace only the die or the entirety of the die and any modifiers ? — Exempt-Medic, Sep 20 '19 at 13:04
@Medix2 As far as I understand, portant replaces only the roll. Any modifiers are added afterwards. Yes, the idea is that you can roll a 2 and use a -1 modifier to turn that into a crititcal miss. — Loid Thanead, Sep 20 '19 at 13:07
I assume you'd want us to consider out-of-combat uses as well? Especially with ability checks, perhaps saying how it compares to spells like enhance ability? — Exempt-Medic, Sep 20 '19 at 13:13
@Medix2, Yes, please. I might add this spell to the general list of spells for my campaign, which means its intended use includes non-combat situations. Is this something I should explicitely call out in the question itsefl? — Loid Thanead, Sep 20 '19 at 13:19
Do you have class restrictions in mind ? Wizard only ? sorcerer ? Warlock ? Would that spell be an option for some cleric domains ? — Bash, Sep 20 '19 at 14:36
@Bash It would be limited to the Wizard spell list, though I would allow it for clerics domans that are thematically similar. — Loid Thanead, Sep 20 '19 at 14:43
@LoidThanead it wouldn't hurt to throw in a line about expected use, but it also works as-is — Ifusaso, Sep 20 '19 at 14:49
What would you (and others) think about making it just a small modifier applied to the roll, say 2 Fudge/FATE dice, plus 1 dice for every 2 spell level bumps? — Xavon_Wrentaile, Sep 21 '19 at 20:48
@Xavon_Wrentaile Adding a die other than the already used dice would make the spell more complex than I'd like. The closes sequivalent (d4) would make it more powerful than the +1 per additional spell level already gives it. — Loid Thanead, Sep 23 '19 at 06:25
I'd love to give it a try some day ; please let us know how it played at your table, once you've refined and tested it! — Bash, Sep 23 '19 at 15:14
@Bash I will, as soon as I have found a way to resolve the conflict between 'I want Divination Wizards to spam this' and 'I don't want my players to trivialize any and every encounter by spamming it until they have a guaranteed success'. That might in itself be worth a new question. — Loid Thanead, Sep 23 '19 at 15:19

score 15 · Accepted Answer · edited Jun 16 '20 at 10:23

As is, it is overpowered.

Replacing dice is a very strong feature, and the divination wizard signature. Making this a 2nd level spell means any wizard can use it... and many will be able to abuse it.

Divination wizards can abuse it, starting level 6.

As wizards of the Divination School recover spell slots when casting divination spells, a 6th level wizard can spam this 9 times each day - and still get plenty of level 1 slots to keep casting. It becomes even more silly at higher level ; at level 17, it means 46 uses per day, not even considering arcane recovery.

It gets worse at level 18, with Spell Mastery

Any wizard will be able to cast this at will. If you don't like the roll you just made, cast it again. You'll eventually roll high / low enough to auto-succeed any ability check, or ensure the guy you intend to charm to auto-fail.

Some solutions?

Option 1: don't homebrew a spell

Making this diviner unique feature a spell makes it available to anybody. It will feel less unique, and remove the spotlight from that subclass. You may prefer to homebrew a feat to allow more portent dice (1 or 2), or short rest recoveries (probably too much). It may be the good way to see it used more often.

Option 2: make it higher level

Bluemoon's 5th level is probably a good start - but depending on the class restrictions you have in mind, level 6 would be a good way to ensure no warlock ever gets to spam this on short rests, or diviners can't use recycled spell slots to cast it again. Following that path, I'd advise you to change the upcasting ability to add more dice, instead of changing their results. A +3/-3 probably does not justify the use of a ninth-level slot, but 4 dice might.

The problem with this option, as pointed out by @Ben Barden, is that it removes access to the spell to low-level casters. You should probably look for other options.

Option 3: 1-round duration

If you like the idea of wizards spamming this (I do!) - limiting its duration is probably the way to go. If a PC wants to spend the entire fight predicting rolls for his allies - let him spend all his actions doing it. If you choose this solution keeping it a 2nd level spell, you'll probably want to limit its use to combat rolls - barring ability checks, to avoid Spell Mastery out-of-combat shenanigans.

Ah, Spell Mastery, now that's a good point; BlueMoon's answer nicely dodges issue that by recommending that it becomes a 5th (4th without the At Higher Levels clause) level spell, but as a 2nd level spell, that's quite the combo... — NathanS, Sep 20 '19 at 13:33
While Spell Mastery does make this extremely broken, the Expert Divination ability isn't as strong as you say. From PHB: "The slot you regain must be of a level lower than the spell you cast" - not the spell slot used. So a Diviner can only recover a level one slot with this, and so at level six could still use this a maximum of six times. (But they sure will have a lot of Magic Missiles available if they do!) I suspect a lot of people are using Expert Divination incorrectly. — fluffysheap, Sep 21 '19 at 14:29
@fluffysheap I did not check before posting - but this very relevant point has been questionned elsewhere. You might want to reopen the debate there ? — Bash, Sep 21 '19 at 15:43
Looks like I might be the one misunderstanding Expert Divination! Thanks @Bash — fluffysheap, Sep 21 '19 at 16:11

score 6 · Answer 2 · edited Jun 16 '20 at 10:23

6

This is overpowered as a 2nd level spell.

This spell can essentially be an "inflict advantage or disadvantage" to any creature's d20 roll, but with the versatility that you know before-hand what value will be rolled. The fact that it takes your action, reaction, and concentration is a hefty price, but it is not enough. Bash also makes a great point, Spell Mastery breaks the game if this is a 2nd level spell, and recovering slots from casting Divination spells also makes this OP.

As a second level spell, a level 14 Wizard (who should do 3 Portents a day) can do 13 of these (and some more with Arcane Recovery). The scaling of the spell with higher spell slots makes this even more broken, with a possible +7 modifier on the roll, and a 35% chance of giving a creature a natural fail or success with a 9th level spell slot.

If this spell didn't take action, reaction, and concentration, I would say it should be a 7th level spell, which can be learned from level 13 on-wards. You would at best do 4 of these a day, with +2 modifiers. However, because of its cost, I would classify this as a 5th level spell. You get to learn it a level 9, cast it 4 times at level 14, and 9 times at level 20, with at most a +4 modifier.

The fact that you lose your turn, cannot concentrate on other spells for the duration, and will also lose your reaction (useful for Shield, Counterspell, or Warcaster AoO), seems like a fair cost at 5th level.

Other solutions to nerf the spell is to remove its scaling, but even then, I think it should be a higher level spell, at least 4th.

edited Jun 16 '20 at 10:23

Community

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answered Sep 20 '19 at 13:20

BlueMoon93

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What about the upcasting feature? – NotArch Sep 20 '19 at 13:22
@NautArch I would leave it as is if the spell is 5th level upwards. It is hard to judge its effect. Anyway, I've addressed that removing that scaling is also a way to nerf the spell, and maybe put it at 4th level if that got removed. – BlueMoon93 Sep 20 '19 at 13:23
Knowing the d20 roll isn't always particularly helpful, especially with mid-range results. I'd mostly just like to know why you think it's overpowered. There's also one big difference between the spell and the Portent feature: you have only one minute to use this spell whereas Portent gives you 24+ hours. – Exempt-Medic Sep 20 '19 at 13:24
As a 5th level spell, what do you think of nerfing that modifier to make it an, at most, +2 modifier rather than +4, if the "At Higher Level" clause doesn't increases every spell level (e.g. 6th or 7th slot = +1, 8th or 9th slot = +2)? Or do you think +4 isn't that big a deal once it's been made a 5th level spell? – NathanS Sep 20 '19 at 13:25
@NathanS At 5th level, I don't think the +4 is that bad. Afterall, you're using your 9th slot to get that modifier, it doesn't seem that OP when compared with other high-level spells. – BlueMoon93 Sep 20 '19 at 13:26
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To help me understand how to judge these things for myself next time, what do you use as a basis to determine it should be a spell of level X? – Loid Thanead Sep 20 '19 at 13:28
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Fair enough; I was just thinking that at 9th spell level, that's a 25% chance of a crit (if the d20 is 16+), but then, also at 9th spell level, wish... – NathanS Sep 20 '19 at 13:29
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@Medix2 Even mid-range values can be used. Consider an enemy that you know some information about (average INT, or high STR). If your party members do anything that interacts with that stat (an INT save spell, or a grapple), you can try to guarantee success. This can vary from table to table, regarding the knowledge of modifiers and such values for the PCs, I recognize that – BlueMoon93 Sep 20 '19 at 13:30
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@LoidThanead That's actually a tricky question. Ideally, you want to compare your spell with others similar. In this case, I went with the Portent feature, I'm not aware of other spells that replace rolls. From there, I paid attention to amount of possible uses, impact at high level play (which requires experience and is very table dependent), etc. The goal of a balanced spell, imo, is to be able to say "Ok, this is useful in these situations, but other spells are better in other cases". – BlueMoon93 Sep 20 '19 at 13:33

score 2 · Answer 3 · edited Jun 16 '20 at 10:23

The problem is not the 3rd-level wizard casting it once; it's the high-level wizard casting it a great many times.

This is fundamentally a spell that itself scales. It can make an ally's attack an autohit (or, if lucky, an autocrit). It can make an enemy's attack (or save) autofail. The more powerful the attacks in question are, the more meaningful this particular spell is. Giving it a few times a day to a low-level wizard isn't an issue. Giving it many times a day to a higher-level wizard is.

The simplest answer to this particular problem, then, is to make that the scaling. Limit the spell to targets of a level (or CR) that is dependent on the spell slot used. What those ranges are is something to be tweaked based on how often you want it to be usable, but any reasonable implementation of this will take care of the "multiclassing warlock" and "Spell Mastery" issues, while still meaning that lower-level wizards can play around with it a little.

Another thing to consider including, in order to open up a bit more space, is to make it impossible for the wizard to target either themselves or saves against spells that they cast. Doing that would make it explicitly a cooperative spell, that would be most effectively leveraged to make the wizard's allies look good. Cooperative powers can afford to be a bit more powerful - they don't steal spotlight, and it increases the fun factor at the table when they do awesome things.

For specific wording, and a possible reasonable progression: Starting as a third-level spell, "This effect may only target creatures of level/CR 7 or less." Then you have level scaling of something like 3rd->7th, 4th->10th, 5th->14th, 6th->20th, and 7th->unlimited. If you were really eager to get at it, it probably wouldn't hurt anything to allow a level 2 version that couldn't target anything of target level above 4.

This results in a slow (if erratic) growth in the max casts per day (for castings capable of targeting the wizard's peers), but keeps them relatively precious at all levels.

Cleaning old comments, but I still think you have a great basis, and your answer would be improved with some wording & cosmetic efforts. Feel free to include this testing sheet if needed. — Bash, Sep 20 '19 at 19:02

score 0 · Answer 4 · answered Sep 24 '19 at 20:10

This is ok

The cost

The two most important resources a caster has in any combat?
Actions and concentration.

This uses up both, as with 1 minute duration you cannot reliably cast it before combat. And in combat you do not want to spend your concentration, which you have only one of, and your action, which most likely you have only two or three of per encounter on something that most likely does not give you anything.

The benefit

You get to roll a die, anything between 7-13 is probably useless, too high for enemy saves, too low for friendly saves.
Higher rolls are good for friendly saves, but those high level spells you definitely want to hit with just do not exist, and the weapons swingers just do too many smaller attacks for any of the to be important enoght for a 2nd level slot, your action and your concentration.
This means only about one third of the results are actually useful, but even those not for you; most of the spells that require a save also need concentration.

And remember, you have to use it before you see the roll, so even if you do not get see it, it is only beneficial if the roll would have been unfavorable, so half the time in the long run.

Higher Levels

Even if you waste a 9th level slot on it¹, you still cannot guarantee a low enogh roll.

Out of combat

Not that bad, the costs matter less.
However, the benefits are still limited. If the party has to climb a rock, whose roll do you replace? A 2nd level slot is a high enough price for some dubious results.

1) you should not

score -1 · Answer 5 · edited Jun 16 '20 at 10:23

Probably Overpowered for its Spell Level

This is a Level 2 concentration spell which lasts only 1 minute (meaning, you will likely only need to substitute the roll in for one combat or skill check). You're probably not using this spell in combat, as your other in-combat options are likely better.

This looks to me like a purely utility spell. That being said, I probably would take it as-is on a higher-level wizard to guarantee important skill checks and force failed saves in niche situations.

This is not an effective in-combat spell. You need to consider not only the effect but the opportunity cost. Would you rather cast this in combat, or Web? How about this or Illusory Force? This or Hypnotic Pattern?

That being said, I think that I probably would take this on a high-leveled wizard to guarantee important rolls for utility purposes, like guaranteeing that my Feeblemind sticks on a monster that I want to Dominate, to make sure my ally's Planar Binding sticks, or to make sure that the party Rogue sticks their skill check. It's expensive, but worth it if the effect of the successful check is big enough. In fact, I think that this spell is probably best used on a Necromancer PC to make sure that their Feeblemind/Command Undead sticks.

Also, I think that the spell is too powerful a choice for Spell Mastery and should not be Level 2 as a result. I think this spell should be level 3, tops, but I don't think that it's strong enough for Level 4, which includes things like Summon Greater Demon, Otiluke's Resilient Sphere and Polymorph. It certainly isn't powerful enough for Level 5. Burning a Level 3 slot for this effect is a big ask.

You want people to actually use your custom spells that you put work into. It needs to be strong enough to be worth taking at that level, but I don't think that I would ever cast this in a Level 4 slot or higher unless it was during downtime (and even then it's highly situational).

I don't think that this spell needs to be scaleable with levels. It works fine at its base.

The replacement of the roll is intended to work exactly like portent does. As far as I see that doesn't influence (much of) your general answer. — Loid Thanead, Sep 20 '19 at 14:40