What happens to items left in Mordenkainen’s Magnificent Mansion?

Recently, the question arose as to what happens when you leave objects you own in Mordenkainen’s Magnificent Mansion. The spell description does not specify if you always conjure the same Mansion, or if it is a different one. So what happens if I leave something like my magic short sword in it? Or even a mundane item, like my mundane pottery?

The spell says that creatures are expelled when the spell ends, and it says what happens to things from the mansion that you want to take outside, but there is nothing about items taken into the mansion. Is there any information in the rules, somewhere?

Can Mordenkainen’s Faithful Hound be made mobile by casting it on a mobile surface?

The description of the Mordenkainen’s faithful hound spell says, in part:

You conjure a phantom watchdog in an unoccupied space that you can see within range, where it remains for the duration, until you dismiss it as an action, or until you move more than 100 feet away from it.

If I were to cast Mordenkainen’s faithful hound to conjure the hound on a wagon, or on Tenser’s floating disk, would the hound then be able to follow me around and remain active for it’s 8 hour duration?

Is the “Bone of Animation” in Mordenkainen’s Tome of Marvelous Magic unbalanced?

I’m running Descent into Avernus.

In a session 0 for one my PCs, they acquired a Bone of Animation, which is an item in Mordenkainen’s Tome of Marvelous Magic.

(This is a pretty great list of magical items on dmsguild: https://www.dmsguild.com/product/291001/Mordenkainens-Tome-of-Marvelous-Magic)


Wondrous item, uncommon (requires attunement)

This item appears to be a regular human upper arm bone. While holding the bone you can use an action to speak the command word and turn the bone into a skeleton. The skeleton reverts to bone form after 1 hour or when it drops to 0 hit points.

The skeleton is friendly to you and your companions for the duration. Roll initiative for the skeleton, which has its own turns. It obeys any verbal commands that you issue to it (no action required by you). If you don’t issue any commands to the skeleton, it defends itself from hostile creatures but otherwise takes no actions.

Once the bone is used, it can’t be used again until the next dawn.

So far, so good. This is a pretty cool item.

We’re now approaching level 5, and my wizard is super excited to use Animate Dead when he levels:

This spell creates an undead servant. … On each of your turns, you can use a bonus action to mentally command any creature you made with this spell if the creature is within 60 feet of you (if you control multiple creatures, you can command any or all of them at the same time, issuing the same command to each one). You decide what action the creature will take and where it will move during its next turn, or you can issue a general command, such as to guard a particular chamber or corridor. If you issue no commands, the creature only defends itself against hostile creatures… The creature is under your control for 24 hours, after which it stops obeying any command you’ve given it. To maintain control of the creature for another 24 hours, you must cast this spell on the creature again before the current 24-hour period ends. This use of the spell reasserts your control over up to four creatures you have animated with this spell, rather than animating a new one.

By comparison to this, the Bone of Animation seems overpowered:

  • It does not require a spell slot to use
  • You can issue verbal commands without using an action

Whereas for Animate Dead:

  • You must expend a spell slot
  • You have to use a bonus action to command the creatures

The only downsides of the Bone is that you can use it only once per day, and the skeleton lasts for at most one hour. But in a typical adventuring day, there is probably one combat encounter that would require pulling out all the stops — so neither of these downsides seems that impactful.

I do understand that Animate Dead scales well, and at higher casting levels you can start to control groups of undead. But it seems very off to me that Animate Dead requires a bonus action to command, whereas the Bone does not. Every similar item in the Tome of Marvelous Magic is the same, so I assume it was a deliberate decision by authors.

The question I need an answer to:

I’m thinking of editing the Bone so that it also requires a bonus action to command. Without this I anticipate my wizard asking me why he has to expend a bonus action when my other PC does not.

Does this modification negatively impact game play or materially change the balance implications for this item?

Are the Tiefling subraces from Mordenkainen’s Tome of Foes specific to a particular campaign set?

Are the Tiefling subraces from Mordenkainen’s Tome of Foes specific to a particular campaign set?

In Mordenkainen’s Tome of Foes (MTF) there is a section on Tiefling Subraces (p.21), which elaborates on how the information about a Tiefling’s ability score increase and the Infernal Legacy contained in the Player’s Handbook relates to Asmodeus. Let’s say the “default Tiefling” prior to MTF.

Under Tieflings Subraces there is a variety of Subrace Traits for e.g. Tieflings associated with Baalzebul or Fierna.

It says this is a DM’s option to include other Tiefling subraces, but I was wondering: Is this intended specific to a particular Campaign Set, or it’s meant to be a global change?

Does Mordenkainen’s Private Sanctum prevent Devil’s Sight from working?

I could compare it to this question about whether the Devil’s Sight invocation allows one to see into Hunger of Hadar, but that question has an easy answer, due to the ‘blinded’ condition it affects the person inside with. However, the spell Mordenkainen’s Private Sanctum does not give the ‘blinded’ effect- it merely states that, in one of its properties:

The barrier of the warded area appears dark and foggy, preventing vision (including darkvision) through it.

Improving terrible spells: Mordenkainen’s sword

The problem

In my answer to “Is the Mordenkainen’s Sword spell underpowered?”, I concluded that the spell is terrible. Critiquing a spell is one thing; improving it is another. So, can the sword be fixed, or is it doomed to rot in spellbooks forever, never to be copied?

First, the original:

Mordenkainen’s Sword

7th-level evocation

Casting Time: 1 action
Range: 60 feet
Components: V, S, M (a miniature platinum sword with a grip and pommel of copper and zinc, worth 250 gp)
Duration: Concentration, 1 minute

You create a sword-shaped plane of force that hovers within range. It lasts for the duration.

When the sword appears, you make a melee spell attack against a target of your choice within 5 feet of the sword. On a hit, the target takes 3d10 force damage. Until the spell ends, you can use a bonus action on each of your turns to move the sword up to 20 feet to a spot you can see and repeat this attack against the same target or a different one.

Mordenkainen’s sword has several notable problems:

  • The sword’s damage is bad for a concentration spell. Over three rounds (assuming all attacks hit), the sword deals 66 damage, while Bigby’s hand deals 108 damage (when upcast to 7th level).
  • The sword’s damage is bad for a non-concentration spell. Crown of stars from Xanathar’s has an hour duration and requires no concentration, but still deals 78 damage over 3 rounds.
  • The sword is inferior to non-damaging options. Why waste a 7th-level slot dealing (terrible) damage to a single target, when you could put most creatures in a forcecage with no save? The sword’s 20 feet of movement each turn also means that it can’t reach mobile high-level enemies, like dragons.

Mordenkainen’s sword also has several features that make it unique:

  • The sword is the highest-level spell that targets a single creature, requires concentration, and purely deals damage. Even if we relax the concentration requirement, only crown of stars (also 7th-level) meets the remaining requirements.
  • The sword allows two attacks on the first turn, but only one thereafter. Getting damage out early is usually better than spreading it across multiple turns, but this may complicate attempts to rebalance the sword.
  • The sword is one of only four leveled wizard spells that only require a melee spell attack. The others are vampiric touch, Mordenkainen’s faithful hound, and steel wind strike.

A solution?

My goal is to keep what makes the spell unique, while fixing its glaring balance issues. With that in mind, the spell remains the same, except for the second paragraph and the new “at higher levels”, which now read:

When the sword appears, you make a melee spell attack against a target of your choice within 5 feet of the sword. On a hit, the target takes 7d10 force damage. Until the spell ends, you can use a bonus action on each of your turns to move the sword up to 60 feet to a spot you can see and repeat this attack against the same target or a different one.

At Higher Levels. When you cast this spell using a spell slot of 8th level or higher, the damage increases by 2d10 for each slot level above 7th.

Do these changes make Mordenkainen’s sword a reasonable, balanced choice for bards and wizards? Would a controller ever consider taking it? Would a blaster ever use anything else?

Does the Mordenkainen’s Private Sanctum spell block summoning creatures into the warded area?

If you secure an area with the Mordenkainen’s private sanctum spell and choose the effect:

Planar travel is blocked within the warded area.

Does this prevent summoning creatures into the area via spells like infernal calling (XGtE, p. 158)?

Planar travel, in this instance, could either mean “willingly moving between planes” or “moving between planes under any circumstance”, and I don’t know which is meant by the spell.

What is the winged creature on the back of the Mordenkainen’s Tome of Foes book?

On the back of the Mordenkainen’s Tome of Foes book, there is a small creature with wings (I don’t know how to crop images, so here’s the entire image):

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What is this creature? It doesn’t match any of the creatures in any of the monster manuals. It kind of looks like an imp, but it clearly isn’t one, and my only other guess is that maybe it’s some kind of homunculus?

What happens to matryoshka Mordenkainen’s Magnificent Mansions?

The following situation happened towards the end of our last session(I am the DM): A player cast Mordenkainen’s Magnificent Mansion, so they could take a break to heal up their comrades and rest a bit.

Then, that player cast the Mansion again (after a long rest) and placed the portal inside the first mansion. Everyone went through before the first mansion disappeared, and expected to return to the main overworld again after another 24 hours.

But technically, the Mansion only expels creatures, not portals to extradimensional planes, so shouldn’t they be thrown out where the first mansion was, an extradimensional space?

I am not gonna do this to them now since this would be the end of the story and not something anyone expected, but still: Would my players be back to the extradimensional space where the first mansion was?