How can I reasonably prevent Manual of Bodily Health abuse? [closed]

Question

I'm running D&D 5e. My players have recently come into possession of a Manual of Bodily Health. The very first thing they thought of was how to abuse it. They are planning on reading it and then burying it in the Feywild. The time dilation in my world means that every day in the material plane is years upon years of time in the Feywild. Rather than having them stack their Constitution bonuses infinitely, how can I reasonably limit this?

The description of the item is as follows:

This book contains health and diet tips, and its words are charged with magic. If you spend 48 hours over a period of 6 days or fewer studying the book's contents and practicing its guidelines, your Constitution score increases by 2, as does your maximum for that score. The manual then loses its magic, but regains it in a century.

The Feywild has been a realm where time flows differently. I used the example of taking a couple of minutes between entering the Feywild has been a total of 2 weeks of waiting inside of the Feywild for the rest of the party to join.

This manual was an item they rolled on a magic item table, and therefore something I hadn't properly planned for. Considering its already very powerful effects, I'm worried about the players following through with their idea of "Let's bury it in the Feywild and use it over and over again! I bet this is something the DM didn't think about!"

Answer 1

The Feywild is a living place too and 100 years is a long time.

Your party is burying the manual of bodily health in the Feywild with only the hope that in 100 years within the Feywild that nothing finds it and takes the book for itself. This is quite unlikely to put it mildly. The next time they comeback to get it, the book has been taken. Maybe something watched them bury it 100 years ago and has long since scarpered or the book has been uncovered by the ravages of time or by mere chance.

In the modern world we see objects and ruins unearthed by dumb luck all the time. It's not unfair for you to maintain the balance of the game.

If this feels cheap to you, then the alternative is to up the pace of your adventures so that the party simply doesn't have time to keep reading the book. Adventures on a tight deadline that forces your party to move fast can stop them from feeling comfortable from reading.

However, you need to be willing to enforce consequences on this route if a player calls your bluff and this option can only hold up for so long as you can keep placing tight deadlines that the party will prioritise over reading the book.

Answer 2

Maybe the Feywild doesn't always run time that fast

There's a table in the DMG which has results anywhere from "days [in the feywild] become minutes" to "days [in the feywild] become years". Maybe your group got an unusually fast-running time transfer the first time they tried it, but maybe that's not always true.

Maybe the book gets stolen

As Falconer wrote, there are creatures in the Feywild that want that book for themselves. Maybe when the group returns to look for their book, it's gone.

Maybe the book only works once per character

The book description doesn't say it only works once per character, but probably very few characters live long enough to use it twice, so that fact wouldn't be widely known. It would be reasonable for you to apply a house rule here -- "you've already learned all you can from this book" or something like that.

Maybe let it work a few times before breaking it

Part of the fun of playing D&D is finding creative ways to accomplish awesome things. If your group is that excited about doing this, consider letting it work at least once or twice. It will make a memorable story.

(In my games, if the group comes up with something creative like the thing you're describing here, I try hard to let it work. Players like it when I do that.)

So, maybe the group leaves the book there and they get three uses out of it before the time dilation swings the other way. Or maybe they leave the book there and it gets stolen but they can figure out who did it and take it back.

The +2 Constitution bonus is not actually that powerful, and letting them get a few of them will not break your game.

Answer 3

Simply forbid the abuse. The specific reason why is just fluff when your concern is strictly mechanical

As other answers have mentioned, you can allow plans like this to partially succeed to any degree you think is appropriate. But when it comes to shutting down abusive levels of a scheme, you can just say no.

In every TTRPG I run where a situation like this even seems like it might come up, I remind my players that I have do not have any responsibility to break the game nor to assist them in breaking the game. Quite the contrary-- the DM has an explicit responsibility to keep the game challenging and interesting. If the players boost their CON scores to 30 then many aspects of the game become trivial, and so executing this plan is the conclusion of the campaign. And not an exciting one. One of your primary tasks as DM is to make sure this does not happen.

They have no technical argument to fall back on, as your time dilation is already homebrewed and takes everyone beyond the published rules. If your group has already become fixated on this exploitative plan then any obstacles to it are likely to feel cheap, unless they appreciate your responsibility to the game. The main impact of this is that it is probably not worth your time to try and whip up a completely satisfying, in-universe reason to limit them as the only reason their idea won't happen. It won't matter if someone in the Feywild steals the book, depriving the party of it forever, or if it's destroyed by erosion or natural disaster, or if you decide that the manual is cursed, or has some other properties which interfere with their current expectations, or if you alter the game's challenges such that their arbitrarily high CON scores are irrelevant.

My experience as DM is that players are often a bit deflated at seeing their cool idea not come to fruition, but ultimately accept that it would break the game to do otherwise. Just last week I allowed my players to choose one magic item each, very rare and lower, from a wealthy genie as a quest reward. I reminded them that their choices were subject to my approval. One of the players wanted Illusionist's Bracers, but the way he'd specced his character out meant that they would be wildly overpowered and so I did not approve them by saying that the genie didn't have such an item in his collection. He was disappointed, but understood.

tl;dr: Abusing the manual will very likely ruin the game, which you as DM cannot allow. Making this clear is the only way to avoid such abuse without making the players feel cheated now that they've already conceived of this plan.

Answer 4

The Feywild's time flow is unpredictable.

First off, the Feywild's fluctuating time flow is an optional rule, but assuming you have decided to use it, there still isn't a single clear "X days equals Y years" comparison to be made with the Feywild, and certainly not the one that's most favorable to the players. In fact, faeries being what they are, I wouldn't be surprised for the realm to go out of its way to foil attempts to use its time warping capabilities to anyone's benefit.

The Dungeon Master's Guide gives a table of possible results to roll on, with the following instructions:

Whenever a creature or group of creatures leaves the Feywild after spending at least 1 day on that plane, you can choose a time change that works best for your campaign, if any, or roll on the Feywild Time Warp table.

Sure, under maximum time compression, 100 years spent in the Feywild convert to just under 26 days in the real world. But the players don't get to just decide that's what it ends up doing. The rule is first, the DM decides what the time differential is, and second, the DM can decide to roll randomly if they want to, only after the time spent there. (Technically this rule only applies to the players coming home after a Feywild trip, but for the moment, we'll assume the same would happen when retrieving an object after leaving it there for a while -- but that is by no means a given.)

If you go with the most random option, they'd have to drop the book over there, wait a month, then come back and see if a century has passed yet. Each time they have a 10% chance of getting the days-become-minutes warping that allows a century there to pass in a month here. Even assuming they could manage this without becoming interesting to the more dangerous elements of the Feywild, even assuming the book doesn't get stolen while it's being left alone for decades on end, they might be able to use the book maybe once a year, on average.

But to be honest, I don't buy this plan. The DM specifically has control over that sort of thing, which is all you need to just say, "No, that's not going to work."

Answer 5

They could simply forget that they buried it in the Feywild

Due to pervasive and powerful Feywild magic, non-fey creatures who leave the Feywild may be subject to immediate memory loss, and may not remember any of their time spent in the Feywild.

The Dungeon Master's Guide (p. 50) provides optional rules for the effects of Feywild magic, including memory loss:

A creature that leaves the Feywild must make a DC 10 Wisdom saving throw. Fey creatures automatically succeed on the saving throw, as do any creatures, like elves, that have the Fey Ancestry trait. A creature that fails the saving throw remembers nothing from its time spent in the Feywild. On a successful save, the creature's memories remain intact but are a little hazy. Any spell that can end a curse can restore the creature's lost memories.

Since you are DM, you could increase the DC, or just rule that they all fell for an extremely strong spike of Feywild magic that also affects elves.

Simply "roll" for them and tell them, that they all don't remember being in the Feywild when they buried the book. So the book is still there and would be working after recovering it and 100 years have passed... but none of them remembers that they where there and put the book there.

Answer 6

100 years is a long time

Each time they are placing a powerful magical artifact in a plane of living magic, leaving it alone for 100 years, then coming back ... and reading it.

This is on a plane where the grass shares gossip.

Cute plan. It would be horrible if something happened to it.

The location has changed

Feywilde is a plane of eternal change and life. Where it was is no longer recognizable. This can provide a location-based adventure.

The book is missing

Someone took the book. You can leave a clue, or no clue at all, or a clue you can reveal later and use as an adventure hook.

A note saying "BRB with book" might be amusing. Or a library card. Or another object of "equivalent" value swapped for it. (Stealing something in the Fae induces obligation, but swapping does not).

The time in the Feywilde alters the book

You know all of the stories of eating food from Faeries? How about rebuilding your body using a book full of Faerie magic?

Would your players feel safe with placing a body altering book into the Abyss, storing it underground there for 100 years, then digging it up and using it?

Silly mortals.

A Faerie replaces or alters the book

Wouldn't it be funny to take a magical book, and replace it with another, or enchant it? I think it would be.

Now, what kind of diet would a Fey try to get a mortal to engage in for a joke?

So, change of creature type (the player becomes a hobgoblin), more extreme shapechange (they become a very healthy frog bullywug, and remember that the book talks about the transformative power of love and royal kisses). An enchantment that makes them obsessed with physical health (do you even lift bro?) A trade, where a random stat is reduced by 2 as constitution increases by 2. The book describes a diet and tattoo program; at the end of it, instead of +2 con, the player has a magical "tattoo" attuned to them via branding (soft pedal this; have a bunch of boring exercise advice you read to them every day they read it. Include a bit of information about body alteration to start, then ramp it up.)

Answer 7

I think this is an issue of conflating in game PC knowledge and out of game player knowledge. Unless the Manual of Bodily Health actually contains the description text, the PCs should have no clue as to the 100 year limit, they just see the text disappear after the first use. Unless they do an obscure lore check or consult some otherworldly fount of knowledge, you as DM have no issue. I'd give your players props for a creative hack but as other answers have posted there are any number of creative ways around them. Anyway, a +2 CON bonus, even for all players, does not break your game (you can just give monsters more hp). Have fun with it.

Answer 8

House Rules for the Manuals of Improvement

I have always house-ruled the following for all of the Manuals:

1. Once read, the Manual disappears into its own pocket dimension and does not reappear until the 100 years passes. This reappearance happens in a random library or bookstore in the Prime Material Plane.
2. Each Manual can only be used once per character.
3. All of the Manuals have protection against detection through magical means. Even Detect Magic doesn't detect them.
4. The Manuals are removed from the random loot tables. They are specific rewards that I purposefully put in the game for the players to find.

These rules keep the players from abusing the Manuals, and I have never had an issue with the players understanding why I use them. I try to make house-rules only when something in the game is too ambiguous or if I feel something is unbalanced. In this case, it is specifically because I feel situations like you are seeing are possible and I wanted to cut off any abuse.

I've always found that players rarely get upset at house-rules, as long as they are discussed, make sense, and are consistent. Don't be afraid to say, "Hey, I've been thinking about this and doing some research and here's my ruling moving forward..." at the next session, even if that contradicts what your ruling in the moment was in the last session. Just avoid retconning unless it is necessary.

Just remember that your rules should also apply to the NPCs and enemies. Don't say they can't do something, and then let one of your BBEGs do exactly that.

Answer 9

The magic of the book is what grants the constitution bonus.

After someone has read the book, it's magic is transferred to them, though it's still the source of the magic. If the book was destroyed through magical means they will lose their powers.

After 100 years pass in the feywild (or anywhere really), the book "regains" the magic it had imbued upon the character, their constitution bonus vanishes and the book is ready to be read again to grant someone new (or even the same person) it's power.