PF - Rise of the Runelords and Legend Lore

[Nibbens]

So yeah...

My PCs learned of the BBEGs name "Karzoug" during their stint in the Skull's Crossing Dam (from the Pit Fiend). Once they were out, they had the bard do Legend Lore (http://www.d20pfsrd.com/magic/all-spells/l/legend-lore). Of course it would take ONLY 2 weeks when I rolled the dice.

So, yeah, my PCs just asked for legends about "Karzoug." I know the Thassalonian Library section is coming up and they will get a motherload of info there, however I want to do Legend Lore correctly.

Regardless, I've never had to deal with this spell before, and it seems a little vague. The exact reading that I'm confused about is:

"When completed, the divination brings legends (if any) about the person, place, or things to your mind. These may be legends that are still current, legends that have been forgotten, or even information that has never been generally known."

So my questions are:
1) If the legends have never been generally known, and therefore the spell provides the legends, how does one go about making these hyper specific and amazing legends about the BBEG "vague" and "lead the PCs to the next source of specific information?" This seems contradictory in terms - and difficult to do.
2) How many legends about Karzoug should I bring mention. There is a ton of information I can provide.
3) On the note of "tons of info" - "vague" does not limit volume. So it should be possible to give them everything, but vaguely... This seems difficult in the way question 1 is difficult.
4) Anything I shouldn't bring up for context of story?

I guess my main concern is how Legend Lore (http://www.d20pfsrd.com/magic/all-spells/l/legend-lore) works. This spell itself seems awfully vague in the terms of information it can provide.

[Geddy2112]

Divination spells, above all others, are the most subject to DM interpretation. These spells are effectively allowing the players to see behind the screen, so what you reveal is mostly up to them.

Now, if you wanted to be short leashed, the spell would reveal the library and a lot of the basic legends there. Perhaps where to search, and some basic fluff background. On the other hand, you could reveal every drop of information the players would gain here, but that would invalidate the adventure and search.

1.What legend lore reveals is just that-legends. Some of these might be tall tales, outright lies, or god awful truths. With vague information, you could always give snippets of fluff and in game story that are incomplete. BBEG can shapeshift? Maybe they see this BBEG or hear a legend about the multi formed monster. Can breathe fire? Villages in flames. It can be as specific or as vague as you want. It might be a split second of an ancient painting. It could be the entire story passed down through a tribe.

2. Up to you. Again, for vague lore a lot of incomplete pictures(and maybe a red herring or two, legends can be wrong) would probably work.

3.You can, as the spell says, gain knowledge of EVERY legend, but not a lot of info. Say Legend lore was cast on Mulan. One part might talk about a girl, one part might talk about how she acted as a man, another about the mongols, another about her martial ability etc. This might only be snippets with a single casting of legend lore. Maybe they see the name of a title of a book, or the library.

4. Anything that would invalidate the plot and make it unfun for the players. You don't want a spell to just end the campaign, but at the same time you want the players to get a bit more insight then just "go to the library cause I am railroading". It would help them to know what to look for, what is important, what is not, etc.