Does D&D 5e have a rule for character knowledge about monsters?

In the 3rd and 4th editions of D&D, there were explicit rules for determining if a character knew anything about a monster before them. In 3rd edition, for example, use of the Knowledge skill with a general DC of 10 + the monster’s HD allowed for determining one fact, plus one fact per 5 points over the check.

Looking at the Intelligence section of the 5e PHB, I don’t see any similar notation. Does 5e provide any guidance as to when a player could use their out-of-game knowledge about a monster, or when the player might be told things their character would probably know in-game?

How much do I tell new players about new monsters?


Background

I am a brand-new DM, about to lead a game for brand-new players. I have a lot of knowledge of rules from playing Baldur’s Gate and Neverwinter Nights over and over, leafing through a friend’s books, and finally buying the three basic books for myself.

Question

How much information should I give to my players about monsters they encounter?

Should I essentially read the entire MM entry to them, or let them figure out how the enemies operate through experience, or (as I assume), something in the middle? Keep in mind, only one of them has even peripheral experience with D&D (they are very good sports for giving it a shot!), so they won’t be bringing background knowledge to the table. For example, do DMs generally let players know what immunities creatures have, or do they let them figure it out by trial and error? What about offensive abilities? For example, if a player has a potion of fire resistance, should I give them a heads-up about the fact that the chimera they’re facing has a fire breath attack?

Discover a Monsters Weakness?

As a newbie player, I’m getting to grips with all my skills and abilities and when to use them.

One thing that’s come up is when we encounter monsters … what do you roll against when trying to gauge a monsters weaknesses, so we can use fire, water, light, etc, against it?

Do different types of monsters require different rolls to understand what their possible weaknesses could be, eg Insight, Nature, Arcana, etc?

Some players round the table are GM’s themselves and very knowledgeable about what to use against monsters, but their characters wouldn’t have a clue, having never encountered them before, so it’s difficult to find the right balance as a newbie who doesn’t want to buy a monster manual or use an online search!

Any advice appreciated! .:. Walts

Can monsters use weapons they took from player characters via Disarm?

Without necessarily getting into whether or not Disarm is a waste of time or not, if a monster Disarms a PC, (page 271, DMG) can that monster use the weapon if it picks it up?

Example…

A Bandit Captain uses its first Melee Weapon Attack to Disarm a PC of their magic sword… then a free action to interact with an object to pick up the magic weapon, and its second Melee Weapon Attack to attack the PC with its new toy, the PCs former weapon?

Multiattack is specific to certain weapons sometimes… can monsters use other weapons not listed in its multiattack?

How can I play monsters and NPCs up to their potential?

In many cases discussions about balance in 3.5 will, inevitably, involve one side or another invoking an anecdote of the time they fought this monster, or a member of that class, and they didn’t suffer the problem being illustrated in the discussion at hand. In many cases it seems like these anecdotes come from a case of the monster or NPC not being played (tactically) or roleplayed (again tactically, since that’s part of 3.5’s roleplaying experience, but also in terms of personality) up to the potential illustrated by its ability scores, powers, and skills.

How can a GM learn to play these monsters and NPCs up to their potential?

The froghemoth has both lightning resistance and Shock Susceptibility; is this an error? Are there other monsters like this?

In Volo’s Guide to Monsters, the Froghemoth (pg. 145) has resistance to lightning damage, but also has the Shock Susceptibility trait, which gives it various penalties whenever it takes lightning damage.

I find this hard to wrap my mind around from a creature biology standpoint, as well as from a gameplay point of view. Is this a mistake? Is there any precedent for a monster having this dual resistance and vulnerability?

Are there any monsters with hypnosis-like abilities and what type of saving throw do they force?

I am wondering if any monsters have a hypnosis-like spell or feature, and if so what is the ability used in the saving throw?

What I mean about "hypnosis" is that it falls short of complete mind control. I.E. they person conducting the hypnosis can control the person except they cannot make them kill themselves, and every time they are damaged the can repeat the saving throw ending the hypnosis on a success and cannot he hypnotized by the same person within 24hrs.

Which monsters &/or items can do ‘somatic’ components for the casting of a spell? [closed]

In Dungeons & Dragons, many sentient beings or devices could learn spells &/or rituals. But who is able to perform somatic components normally done by a humanoid of 3′ to 6′ height? Previously StackExchange has suggested this is up to the DM – is such a ruling sufficient here?

Concerns:

  • Oozes: ambulatory… possibly with pseudopods – is this enough detail?
  • Fae: if only 3" tall (6-7 cm) are their hands still large enough?
  • Magic items / animated parts: would an animate embossed cameo within a ring, necklace or coin be enough?
  • Sentient / Awakened creatures: octopi, trees, wolves or squirrels: do paws, branches & tentacles count?
  • Do gesturing images within mirrors (possibly up to full humanoid size) also count?
  • Handicapped: how many fingers/thumbs can one lose and still cast spells?
  • Is giving this ability to illusions, be they permanent, programmed or projected, a logical yet terrible precedent?

Obviously these are all answered just by knowing how much one needs move to trigger somatic components. I cannot find this answer, even in previous versions of D&D.

How do you handle monsters using social skills vs PCs?

I’ve checked the books and can’t find an answer by RAW other than the DM decides, so I’d like to know how people handle this in their games. What happens if a thug tries to intimidate/persuade the PCs? Do I roll vs the character’s skill (and which one) or set a DC based on how difficult I think it is? Most of the time I just describe the monster’s actions and let the players tell me how their character’s react, but the monsters have those skills listed in the Monster Manual for a reason.

What do you think is the best to handle these checks in order for the monster be effective, have the same fail chance as the PCs, and avoiding slowing down the play or making the players feel cheated?