First off, I'll admit the title was not what I was expecting. We have "newer" players who have been around for months up to a couple years and
still don't know the "rules." Do I add proficiency bonus to damage? If I can do this as a bonus action, can I use my action to do it? My CON is 15, that's a +3 modifier, right? How much ki do I have again? And so on...
So, if I had players who
actually knew the rules, I'd be thrilled!
But, I digress...
So, I my game I add lots of spells beyond what is in the couple of adventure books. Roughly 5,000 spells and counting.
That is A LOT of spells... Frankly, I think 5E already has way too many and well over half of them never get used. It is fine wanting more "themed" magic of course, but IME reskinning and narrative take care of that.
So.....enter a small handful of players. They say that they should know all the "rules" before we start playing the game. They note they know all the published spells. So they say if the DM adds spells to the game, they should get the full spell write ups before the game. The players must have all the game rules.
I'm not so sure we count things like spells, magic items, monsters, equipment, and other such things in the game...as "rules"?
No, they don't. Regardless, if a player does know something of a spell, or magic item, or whatever,
how does their CHARACTER know? Metagaming is a big issue for me and something I take very seriously. As DM, I have infinite latitude in what I do when I run the game. So, the last thing I want is for a player to say, "Hey, I know that, it doesn't work that way!"
For example, in a high level champaign I ran the PCs were off to kill a red dragon who had slain the local "protector" silver dragon. I dropped hints along the way, but they were shocked after all their preparation and planning when the "red" dragon breathed COLD on them! There is a story reason why, and the hints should have made them suspect something odd was going on, but they chose to ignore them because (as players) they thought they knew better.
"Rules" are mechanics and features. If a player's 5th-level sorcerer can cast
fireball, then yes they know about it and might even know about other 3rd level spells. But if they are hit with
cloudkill, the PC probably doesn't. They certainly can't cast it even if they did. Now, knowing how to do the mechanics of the game as a player, knowing what the features of your PC can do, what your spells can do, is what players should know.
It isn't fair to change how a mechanic works unless the players understand that beforehand. For example, if you wanted a gritty, lethal game, and allowed only one death save instead of three, or changed the DC from 10 to 15, players have to know those things before hand as those are basically your houserules.
The players don't know about a spell for a single encounter, then just "remember" and become experts on the spell?
But knowing how a spell works that they've never encountered and seen for the first time? No, absolutely not. That is metagaming at its worst!
So....do things like spells count for "knowing all the game rules"?
Again, absolutely not. Knowing if you cast a bonus action spell, you can only cast a cantrip on your turn, is a rule. Knowing what "Wernak's Waterfall" does, what level, etc. is NOT a rule.
How does "lore" and "game rules" mix? The lore of a spell can give you a lot of information about the spell....but the "lore" does cross over with the "stats" of the spell. Things like spell range, targets, damage type, effects, duration are al "lore" information, that is also "stats/game rule information". The Stats give you the spell lore for free.
Is it "too much" of a "burden" to force players to use Downtime to learn new spells?
A PC can never learn a spell simply by encountering it, or even know all the parameters:
"My PC saw that warlock cast Eldritch Blast from 60 feet away, but I know he could have hit us from 150 ft!"
Why would they know that? They saw the spell at 60 feet, so as far as the PC is concerned, the range is
at least 60 feet, it might be more, or maybe that was the maximum range, especially if the warlock
moved forward before casting it.
The parameters of a spell, the stats of a monster, etc. are lore, but unless the PC has somehow learned it, they don't know it, and the player doesn't have to know it either.
Now, for many things concerning lore I like to use ability checks. There are many things a PC might have encountered or heard of at some point prior to adventuring. Spellcasters who have a spell in their spell list can make a spellcasting ability check against a DC of 8 + double the spell level. If the spell isn't on your list, or you are not a spellcaster, I use different skills for the ability checks: Arcana, Nature, and Religion.
For magical items, I use the same skills, but also some tool proficiencies, like Smiths' tools for magical armor and weapons. The DC depends on the rarity of the magic item.
Common: 10
Uncommon: 15
Rare: 20
Very Rare: 25
Unique: 30
Otherwise, the PCs
can research about an item or use magic like
identify. Research takes downtime and gold, but can reduce the above DCs by 5 to 10.
Again, PCs can have knowledge about creatures before they encounter them. So, for creatures, I use the following skills:
- Arcana: aberrations, constructs, dragons, fey, monstrosities
- History: humanoids, giants
- Nature: beasts, elementals, oozes, plants
- Religion: celestials, fiends, undead
The DC depends on the detail and obscurity of the information, but mostly follows the DCs for magical items above.
- Common (DC 10) includes name, type, size, primary attacks methods
- Uncommon (DC 15) includes AC (+/-1), hit points (within 5-10), speeds, resistances, senses, skills, languages, secondary attacks or spell use, and CR (+/-1)
- Rare (DC 20) includes ability scores (+/-1 modifier), immunities, saves (not the value, just proficiency or not), features, special actions
- Very Rare (DC 25) is legendary actions
Now, although some things might fall under special actions, like Breath Weapons, if it is seriously common knowledge then there is no check--like dragons having breath weapons and what they likely are.