It beats stipulating limited omniscience for PCs and NPCs, such that they know all the strengths and weaknesses about all monsters.
If I can have an uncle that knows about monsters that I have knowledge of, I can have an uncle that knows about monsters that I as a player do not have knowledge of and that he has told my PC about. If trying to metagame knowledge in signals to the DM that the players don't want to pretend not to know a weakness, then having an uncle tell you about the new monster signals the DM that the players do not want to lack knowledge of monster weaknesses.
It makes no sense for a group to want to use player knowledge about trolls out of a desire not to have to feign ignorance, but but okay with feigning ignorance about vampires and golems.
Your claim - which I have just quoted - was that if a player uses the
uncle device to underpin an imputation to his/her PC of his/her knowledge about trolls, then that player will also want to use the same device to have the GM inform him/her about new, hitherto unknown weaknesses.
But that claim was, and is, unfounded. ecause If a player
don't actually know, then when playing an ignorant PC who tries to guess the weakness, s/he is not
feiging ignorance.
inclusion after play begins in my game needs to make sense with what is already know about the PC, and cannot be used to "cheat" the player's way through the current challenge.
In 4e, at least, t's not cheating to know that trolls need fire to kill them even if the topic has never come up before in the campaign. And it's not cheating to impute that knowledge to one's PC.
Or to put it another way: there is no rule in 4e that says
In a given campaign, the first time trolls are encounteed players who know their weakness are obliged nevertheless to pretend that their PCs are ignorant of the weakness, until something happens to confer that knowledge in the course of play. Nor is there any rule that even hints at this.
hawkeyefan said:
No edition restricts the addition of background after play has started.
No edition allows it, either, which means that it is not allowed unless the DM allows it.
From the 4e PHB, p 18:
Roleplaying
The Dungeons & Dragons game is, first and foremost, a roleplaying game, which means that it's all about taking on the role of a character in the game. Some people take to this payacting naturally and easily; others find it more of a challenge. This section is here to help you out, whether you're comfortable and familiar with roleplaying or you're new to the concept.
Your character is more than a combination of race, class, and feats. He or she is also one of the protagonists in a living, evolving story line. Like th hero of any fantasy novel or film, he or she has ambitions and fears, likes and dislikes, otivations and mannerisms, moments of glory and of failure. The best D&D characters belnd the ongoing story of their adventuring career with memorable characterisitcs or traits. . . . A well-crafted character personality expands your experience o the game dramatically.
What follows this is a series of headings, which suggest various ways of developing the non-mechanical aspects of one's PC:
Alignment,
Deities,
Personality,
Mannerisms,
Appearance and
Background. Nothing suggests that all these things must be specified in advance of play - and the general tenor of the introductory text, as just quoted by me, is that someone might do this as they go along to enrich their RPG experience.
Then there is this, at p 258, under the heading
Quests:
Sometimes a quest is spelled out for you at the start of an adventure . . . You can also, with your DM's approval, create a quest for your character. Such a quest can tie into your character's background. For instance, perhaps your mother is the person whose remains lie in the Fortress of the Iron Ring. . . . Individual quests give you a stake in a campaign's unfolding story and give your DM ingredients to help develop that story.
Complementing that text from the PHB is this from the DMG (p 103):
Player-Designed Quests
You should allow and even encourage payers to come up with their own quests that are tied to their invididual goals or specific circumstances in the adventure. . . . Rember to say yes as often as possible!
Nothing in what I've quoted is unrepresentative of 4e; it is typical of it. 4e does not encourage the gating of player contributions to the fiction - in the form of backgrounds and backstory, PC goals, etc - behind GM veto and tight GM control. Quite the opposite.
If a 4e player knows about trolls, and imputes that knowledge to his/her PC, that is not breaking any rule of the game. If the player comes up with some bit of backstory to give colour to that imputation of knowledge, that is not breaking any rule either. 4e simply doesn't work in the way that you are describing.
It's indeed bizarre that this even needs arguing - it's not like people who didn't/don't like 4e were jumping at shadows. There are actual features of the game that make it different from (say) typical approaches to 3E/PF, and its orientation towards player contributions to the shared fiction - which has obvious implications also for the GM's role in that respect - is just one of them.