Ad Astra Per Arcana
Knowledge Forbidden Lore
Knowledge (Forbidden Lore) (None)
You know That Which Should Not Be Known. You have had horrible supernatural experiences and read forbidden tomes, learning truly dark secrets that have challenged everything you thought you knew. Since these revelations defy logic or commonly accepted fact, it does not matter how intelligent or wise you are when using this skill—only how much exposure to these dark secrets themselves you have experienced.
Answering a question about the horrible deities and secrets that lurk at the edges of reality has a DC of 10 (for really easy questions), 15 (for elementary questions), or 20 to 30 (for difficult or really tough questions). Unlike in other fields of study, there are almost no really easy questions associated with this dark knowledge.
You can use this skill to identify monsters and their special powers or vulnerabilities. In general, the DC of such a check equals 10 + the monster’s HD. A successful check allows you to remember a bit of useful information about that monster. For every 5 points by which your check result exceeds the DC, the GM can give another piece of useful information.
The GM can decide which monsters are subject to the Knowledge (forbidden lore) skill and which monsters are subject to one of the standard Knowledge skills. For example, the GM may rule that Knowledge (the planes) is still the relevant skill for learning or knowing about outsiders, rather than allowing them to be iedntified by Knowledge (forbidden lore). However, in most campaigns that use the Sanity variant, aberrations and oozes should be able to be identified by Knowledge (forbidden lore) rather than by Knowledge (arcana) and Knowledge (dungeoneering) respectively.
Usually none. In most cases, making a Knowledge check doesn’t take an action—you simply know the answer or you don’t.
No. The check represents what you know, and thinking about a topic a second time doesn’t let you know something that you never learned in the first place.
You cannot gain ranks in this skill by spending skill points. You can only gain ranks by reading forbidden tomes or having experiences with horrible creatures. In some circumstances this skill can adversely affect your Will Saves vs. certain opponents as adjudicated by the DM.
You cannot take the Knowledge (forbidden lore) skill during character creation. However, the skill has no maximum rank; your level does not limit the number of ranks in Knowledge (forbidden lore) that you can acquire.