Clarify the situation
Whenever my players propose a plan that will in no way work, I first assume that I didn't describe things well enough.
Rogue: I sneak into the throne room, steal the document we need, and leave.
DM: (This guy must have a death wish. What am I missing?) The hallway leading up to the throne room is brightly lit by torches at ...
The class played doesn’t matter, and arguing about it only hurts your position
This situation really, really wouldn’t be any better if she was playing a sorcerer. If she ignores her prepared spells, why wouldn’t she also ignore her known spells?
You imagine that it will be easier for you to keep a sorcerer in line because it will be easier for you to keep ...
Avoid the DM vs Player trap
It looks like you may have fallen into that trap, based on how you presented the problem. This isn't a matter of a "fair fight" between a monster (or a group of monsters) and a PC. It's about the player making choices that have costs. This player gave up more offensive power to be better at defense. Honor that choice.
This is not metagaming
The only AC increase that is not immediately visible in this case is from the fighting style, and that is a +1. All others are readily apparent in the game world, unless measures are taken to hide them (eg. disguise self). Heavy armor and shields are quite obvious and even low-intelligence beasts recognize that they have a hard time ...
This looks like a job for a good set of props!
Let her roll a wizard, but spice things up a bit so that preparing spells becomes less of a chore.
From my experience, most of the time that players are ignoring the "prepare spells" rule - for Wizards, Clerics, and whatever else prepares spells - it happens not because of malice, but because this is a very ...
Deal With This As You Would Any Player Overstep
As it happens, I have had players try to insert real-world but inappropriate cultural influences into a setting of mine. In my case it was Japanese influences into a very European-themed fantasy world.
But this was not so different from the time someone tried to bring Japanese influences into an actual ...
This is known as a "re-spec", and it's reasonable on occasion.
While changing one's character levels isn't a standard rule in D&D 5th edition, it's not unreasonable to allow a character to change a poorly-built character on a one-off basis like this. In fact, the Adventurer's Guild organized play rules explicitly allow low-level characters to do this:
You have to be poisoned to take the damage (he is correct)
The description of the Potion of Poison says:
If you drink it, you take 3d6 poison damage, and you must succeed on a DC 13 Constitution saving throw or be poisoned. At the start of each of your turns while you are poisoned in this way, you take 3d6 poison damage. [...]
If you don't fail the ...
Add the modifier (+2)
As you say, agonizing blast allows one to "add your Charisma modifier to the damage [*eldritch blast] deals on a hit." (PHB p.110, emphasis mine)
Your Charisma modifier is +2, as you can see from PHB p.13. (Or many of us end up memorizing the mathematical rule: "subtract ten, divide by two, round down" to get from score to modifier.)
It sounds to me like you and the player have an out-of-universe disagreement, but you've been trying to resolve it by using in-universe language.
The player is saying, "My character wants to assassinate the government official" (in-universe language). What they really mean is, "I want to accomplish this objective in a dangerous and exciting way" (out-of-...
Mage Hand cannot directly trip a creature, but might be able to indirectly do so
Can't directly grab a creature
Spells do what they say they do and mage hand does not grab creatures as creatures are not objects in 5e.
Can lift 10 lbs of material in the path of a creature's path
An alternative attempt might be to use mage hand to lift a board, stick, or ...
Insightful fighting is a good option to have
Yes, attacking with advantage, as well as sneak attack, when hidden is great, but there are at least two reasons that Insightful Fighting could sometimes situationally be the better choice for your bonus action.
Hiding isn't always possible
Just because your Rogue has Cunning Action and can hide as a bonus ...
My idea is that there is a hidden pirate witch on board that can get a lightning bird to attack once a day, or something, but that she needs to burn incense as a consumable part of the spell.
This is actually exactly just what you need already. Monsters and adversaries in 5E do not need to follow exactly the same rules as PCs, and in fact in many cases ...
No, probably not unbalanced
The rule on Improvised Weapons states in part:
Often, an improvised weapon is similar to an actual weapon and can be treated as such. For example, a table leg is akin to a club. At the DM's option, a character proficient with a weapon can use a similar object as if it were that weapon and use his or her proficiency bonus.
The spell does not require existing vegetation
Entangle (PHB, 238) simply states:
Grasping weeds and vines sprout from the ground in a 20-foot square starting from a point within range.
The magic simply makes the weeds and vines appear.
This is in contrast to spells like catapult that specifically require you to use something pre-existing in the ...
Dispel Magic works by targeting:
Choose one creature, object, or magical effect within range. Any spell of 3rd level or lower on the target ends.
You can target the effect, mirror image, or you can target the creature that has it. The specific rules around dispel magic allow for targeting of a spell effect when normally you don't (such as the ...
The word "class" is being used in two different senses here.
Noble, as a social class stratum in a Feudal/Medieval setting, is a different use of the term than "Class" for a PC such as Druid, Fighter, Ranger, Wizard, etc, that has a progression from level 1 - 20 with game mechanical benefits.
Answer: Noble is a background for D&D 5e, not a PC class.
Embracing player ideas can build their enthusiasm, and is there much to complain about if you put Thor or Odin next to the Raven Queen?
A Comedy Improv skill that is often talked about in D&D is the princible of "Yes, And..." In Improv it means that if a scene mate walks in and says "Look how nice it is outside in this park." ...
There is no time pressure
It is expected that at this point of the adventure the characters have eliminated the threats of the Cragmaw Hideout. They have defeated Klarg, and in doing so either eliminated the last of the threats there or demonstrated to any remaining goblins watching that the characters are not to be messed with, as their (unpopular) leader ...
True seeing, 6th-level spell
This spell gives truesight which allows to
perceive the original form of a shapechanger or a creature that is transformed by magic
without any check/DC.
Dragons don't have the shapechanger tag, but their Change shape ability does specify that it is magic :
Change Shape. The dragon magically polymorphs into etc.
Mage Hand should not be able to trip creatures
The description of mage hand specifies what it can be used for:
You can use the hand to manipulate an object, open an unlocked door or container, stow or retrieve an item from an open container, or pour the contents out of a vial.
Note that this does not include interacting with creatures.
Yes, this is fine. It's unlikely to lead to problems.
In my games, I use a more aggressive rule. I tell players: "I want to make sure you're playing the character you want to play. Between sessions, if there's any decision about your character that you feel wasn't the right choice, feel free to change it. You can change your spells, your feats, your ...
Invisibility can't make targets visible to each other
The description from the invisibility spell states that the affected targets are invisible so that really is all it does. This is commonly known as spells only do what they say they do.
If the Invisibility spell allowed a mode where targets were invisible but able to see each other this would have to ...
Once. Not once per day, or once per casting, but simply "once". The meaning of "once" in the English language is clear, and means you can't benefit from it a second time.
If a spell or something can only be used once per day or once per long rest, it says so in the description. The spell ceremony is a rare case where you can only benefit from ...
The Hydra uses one reaction to run away
The Hydra's "Reactive Heads" feature states that for every head beyond the first, the Hydra gains an extra reaction that can only be used for opportunity attacks. This means that the Hydra has one "normal" reaction, which would be consumed by Dissonant Whispers.
There are two reasons why the Hydra would not be able ...
The DMG says:
Some DMs prefer to run a social interaction as a free-form roleplaying
exercise, where dice rarely come into play. Other DMs prefer to
resolve the outcome of an interaction by having characters make
Charisma checks. Either approach works, and most games fall somewhere
in between, balancing player skill (roleplaying and persuading) ...
You need to be holding both weapons when you Attack in order to use Two-Weapon Fighting - and attacking with a greatsword requires both hands.
You have the Dual Wielder feat, so it doesn't matter that neither weapon is light. So far so good, however:
The Two-Weapon Fighting rules state:
When you take the Attack action and attack with a light melee ...
Lunging Attack can only be used on melee attacks, and nets are ranged weapons
The description of the Battle Master fighter's Lunging Attack maneuver says ((PHB, p. 74; emphasis mine):
When you make a melee weapon attack on your turn, you can expend one superiority die to increase your reach for that attack by 5 feet. If you hit, you add the superiority ...
This will not make the chain you're looking for.
While the movement from Dissonant Whispers does provoke opportunity attacks, and War Caster permits Dissonant Whispers to be cast in lieu of an opportunity attack, all of this is limited by the target's action economy:
On a failed save, it takes 3d6 psychic damage and must immediately use its reaction, if ...
Provided you obtain enough of them and have enough time to cast them all, using 9th level spell scrolls would allow one to cast a lot of 9th level spells without a long rest.
The DMG has rules for granting epic boons (starting on page 231) that include:
Boon of High Magic
You gain one 9th-level spell slot, provided that ...