Fair enough. But in medieval fantasy wouldn't orcs, goblins, and kobolds be nearly as common as the boar, deer, and wolf? A D&D knight would be well trained in the manner of monsters he or she might encounter, before setting foot in their first dungeon.
Even the commoners would know a handful of beasties, passed down parent to child in the form of nursery rhymes, fireside tales. and lessons.
Everyone knows about fire-breathing dragons. It's when that dragon turns out to be a benign benefactor that things turn interesting.
I live in an area where they hunt at least elk and white-tailed deer, but if I saw one in the forest I wouldn't necessarily be able to tell which it is. Similarly, even if you knew orcs are greenish humanoids, would you be able to tell if you are looking at an orc or an ogre, or maybe something more exotic?
I handle this by asking no rolls for very common monsters (in the area the characters are from), and usually telling them the monster's type without a roll (so a dragon is a dragon).
One thing to keep in mind is that information is INSANELY easier to come by in a literate society with the printing press than it would be in most D&D faux medieval societies. And the internet then hugely increased what we consider "normal" access to information.
So while I agree that the most common local monsters would be recognized and there would be folktales about many other monsters this should NOT translate into most people knowing most things about most of what they encounter.
While it is flawed I like the idea that you need in character knowledge skills to get in character information on monsters. What is needed are better guidelines for difficulty numbers and what is known. Oh, and more skill points for those poor fighters
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Yeah, pretty much all of this is true.
Anyone going a'venturing is going to know an Orc or Goblin or (depending on where they're from) maybe hobgoblins, kobolds, bugbears too. Perhaps, if they are nearby, the difference between ogres and trolls.
More than that, it's a character by character kind of thing. The wizardess will recognize/be able to identify a pseudo-dragon (a.k.a. "a lap-drake" in my world) so commonly kept by mage-families in her magical homeland.
The druid knows, specifically, what a troll is and how to defeat them, various types of faye, maybe that the party needn't attack that stone giant or treant, they're "nice enough folks...most of the time."
The knight from the kingdom that just concluded a 20 year "war"/attempted invasion with "the Spider Queen", is likely going to know every possible thing there is to know about drow, driders, giant spiders, several types of demons, etc. etc.
Pretty much everyone knows (due to ghost stories or just plain local history) what most undead creatures are.
But at the same time, it took one group of mine quite some time before they realized that the townsfolk telling them about "the dragon" that was attacking caravans outside of town, really could mean any kind of giant reptilian creature.
"The Demons" that seemed to harangue farmers and kings, across the realms, were any number of curious beasts or magical creatures. Made it particularly nice/enjoyable for me when they encountered an
actual demon. heh heh.
But yes, I do like to keep in mind that not every character will know what every creature is. And description is significantly more fun "this picture here"...unless, you know for sure, none of the players have seen it before. But it is sometimes most expedient. Regardless, I definitely want pix of just about everything (that isn't a normal real world animal).
And yeah, those Kenzer pages are pretty much exactly (maybe minus the half-page of narrative) the kinds of entries I'd like to see...but if it could work into 1 page...or closer to 1.5 pages instead of a full 2, would probably be better for the 5e MM.