Left he goes, hasty and powerful and seeking seeking seeking knowledge.

The library is cavernous, grand and ruined, many of the shelves toppled or empty or burned. Those that remain would certainly hide an ambush well. 

"Forward! You don't want these books, mundane as they are. The real stuff is hidden in the sealed vault. Here, let me show you the way..." 

The Acolyte will pour his Power into his body, pounding through the aisles hopefully faster than potential ambushers might expect. His staff is held in white-knuckled grip, his mind aflame. Anything that moves wrong in his passing will be less than shreds.

As he reaches the location of the vault, hidden behind a great stone-carved mural of the five great gods of Kislev, a pair of Pink Horrors will leap out from their hiding-spots, each a mess of limbs and claws and teeth spitting alien pink flames at the Acolyte even as they charge him. 

They are more than flesh, more than substance. Flame meets flame, a battle is waged beneath and behind reality. The Horrors are mighty, but the Acolyte is mightier. With great effort and fever the Horrors are sundered. In the next instant, the Acolyte turns his attention to the vault, feels its strength in his mind, and sharpens the sundering thoughts to sever it from the wall and open it's mouth of hidden treasure.

Behind him, each fragment of pink horror reforms as it falls to the ground, turning into a set of four Blue Horrors, no less twisted, and no less capable of spitting fire at the Acolyte's back. 

The Acolyte's protective flame spares him the burning for long enough to notice, though he's singed with sizzling, fizzling, buzzing ashes of chaos. Trickery! He leaps into the air with power and height unbecoming of a man of flesh and bone, unleashing sundering flames upon the horrors again before smashing into the Vault at an angle, vibrating with Power.

This time, the demons merely dissolve into the aether, as is right and proper. 

"You know, if you want to get into that vault, all you need to do is draw on the power of the dhar... Here, let me tell - Oh. You seem to have that in hand." 

The vault wall is well-warded, even after all these years, but they fall before the Acolyte's exertions. Inside, is a small room walled in obsidian, quite clear of dhar until the door was opened. On pedestals, also obsidian smoothly carved, there lie three books. The first is bound in human skin and bone, as old as dirt, and written in a spidery hand is "The Carrion Book of Shyish". The second is a huge codex, made from rough parchment in large sheets, with a title written crudely in dried blood and a hand larger than any humans, titled simply "The Gods". The third is a simple book of cheap paper and cardboard binding, the sort that could be found by the thousands in any city, with a printed title declaring it to be "The Architect of Fate". 

Wow! All three of these seem they might be chock full of forgotten knowledge and magical secrets, just the sort of thing the Acolyte came here for. Still, this was pretty serious vault and he didn't exactly come in through official channels, so he'll toss a loose leaf of paper on to each, and then tap each with his staff, and give them some consideration with his knowledge of Determination before handling any of them directly. It wouldn't do to have gotten this far only to be taken out by some curse laid on the books.

An excellent plan, because and all three pedestals shine some form of occult radiance at the first thing to touch their pedestals and The Carrion Book of Shyish is in fact cursed with a fairly serious lifedrain curse that gives up after a minute or two of scrabbling at the edges of The Acolytes Determination. 

Well if it doesn't want to be read and have its knowledge spread, he will have to oblige it! He can always come back for it once he's more familiar with the local magic and developed some more nuanced countermeasures than tanking its malevolence directly to his soul. If The Gods and The Architect of Fate are more peaceable, though, he'll go ahead and wrap them in his sash, held against back, right underneath the tainted skull. The added weight is considerable, especially the larger tome, but nothing he can't handle.

This looks like it'll be a lot of reading, especially if either of the two have passages in languages or scripts the Acolyte is less familiar with, and one thing he's learned well is that the midst of a dangerous ruin is not the place to take a seat and study. With his modest haul, the Acolyte will make for the exit.

A few more demons make attempts on his life on the way out, but the worst of them is some kind of giant screaming manta ray that attempts to ram him through the doorway of an empty classroom. Nothing serious. 

He can return to the open, and somewhat less intensely corrupted, air of the Praag merchant district in good order. 

That was still quite a bit of a workout, even for him. He can understand why it'd be considered a death sentence for someone without magic, or magic less well-suited to high-intensity combat than his knowledge of Fire. It was pleasant to have a bit of guidance, though it seemed a little...naive, almost? Perhaps whatever spirit was haunting that place had grown unused to visitors after so long.

Regardless, he'll climb back over the wall, exult in the late morning air, before finding somewhere reasonably quiet (perhaps his room back at the inn, or a less-cursed library) to open these tomes up and get to studying.

Praag doesn't seem to have a library, or at least, no public ones - asking around will get him directed to bookstores, or a little embattled temple of the god Verena, whose bronze-armoured knights tell him their libraries aren't open to the public here but he should visit the ones to the south, they're excellent (and then peer suspiciously at his backpack). 

"I'll add that to the list of potential destinations to consider..." He looks from the knights to his loot and back. "Something amiss?"

"Would you happen to have some interesting books there?" Asks one of the knights, her tone halfway between "cop who wants to strip-search a perp" and "curious fellow book nerd" 

Well, if she wants to take them away he’ll just ask why, and if he doesn’t agree with her reasons he can just take them back. “Indeed, I freed these from the Fire Spire just earlier today.” He shares non-chalantly as he unties them from his sash.

Her eyes are filled with a hard look. "Are you aware that The Architect of Fate is considered classified material of the blackest kind, and owning or reading it is heresy subject to immediate execution?". A gesture has one of the other guards going into the temple, presumably to obtain reinforcements.

"Not at all. I haven't had time to look at the law books since I arrived here and I didn't anticipate needing to so soon. Can I ask why it's classified?" The Acolyte remains relaxed, albeit through a conscious effort. He'd really rather not have to fight, and running off when he just got to the city yesterday would be rather disappointing, so he's really hoping they've got a good reason.

"It contains heretical material relating to the chaos gods. We are obligated by our faith to prevent such knowledge from being spread to those who would misuse it." 

Yep, here are the reinforcements. A dozen men and women in the same bronze armour and spears, plus another dozen who've clearly just grabbed weapons and jumped to it. 

Chaos gods. He's had them explained to him before, twice. The headman and the hag both took an absolutely serious tone when warning against them, and the former was very careful to speak of them only in whispers under the cover sanctuary. That's enough to make him give some credence to their worry. He doesn't personally think he'd misuse such knowledge, he has a rather high opinion of his ability to put knowledge to good use, but he recalls Pogodarastet's words on a particular god and his potential vulnerability to it. He'll pull the smaller book from his back and ask as he hands it over, "Would you happen to know which of the four it describes?"

The guard-templar thinks for a moment, not about the fact, but about if it's wise to communicate that fact, as she takes the book. "It is a book about Tzeentch. Would you like to come with us? You have been cooperative, and while your other book is not known to us, if it was stored with a known book of such calibre, it might also contain materials that should not be allowed to the public. You will be duely rewarded for your contributions on this matter."  

That one, oof. The Acolyte practically drops The Architect of Fate into the guard's hands in disgust. As a seeker of knowledge, there are few things that he dislikes more than those who hide the truth, but those who twist it certainly make the cut, and that seems to be this Tzeentch's entire deal, more or less. He's also revising his opinion of the whispering spirit he encountered in the Fire Spire as well. It may still have simply been unaware, but an association with Tzeentch introduces the very real possibility that it was playing some kind of trick.

"With this new information you've given me, that sounds eminently reasonable. Please, lead the way."