Background
Vathek the Merchant found the Key of Sezrekan in a 0 level funnel. The Key contained rules to allow a 0 level to possibly advance to 1st level wizard, if the player wishes. It was very obscure about the contents, being left up to the Judge to decide. However, the Key would eventually turn the possessing wizard (assumed) character to the chaotic alignment.
Vathek is Lawful. When the player would advance to 1st, I was going to enforce an alignment change to Neutral. Upon advancing to 2nd, he would turn completely chaotic.
This player is not going to play for the foreseeable future, so there will be a gap when the other players will play and advance events in the campaign.
While Vathek's player (Sam) was gone during the last session that introduced a new player, (Jim) and his four 0 level PCs. For reasons of continuity not related to the 0 level funnel, I decided that the village of Stygholler has a merchant shop owned by Vathek with a "rare books" sections, and a book on local history.
Currently...
Enter Samuel the Orphan (Jim). Soon to advance to 1st level wizard, the player has his sights set on specific spells already.
I rule that in order to gain these spells, Samuel needs to have a source. He cannot just have these spells "pop" into his head out of thin air. There must be a sense of continuity and agency.
In campaign time, weeks pass (much like it has in real life). Samuel believes he has the ability to become a wizard. He has dreamt of magical powers and spells. The dreams are possibly the result of something calling to him...
Prepping for the next session:
It is discovered that Vathek, and his erstwhile companions (also Player Sam's PCs) have mysteriously disappeared. Since they are a part of the Company of the Brass Well, the other PCs should be interested in their fate. They investigate Vathek's shop, only to discover a partially burned study with the Key sitting in the middle of a seven pointed star in the middle the floor, melted blobs of candle wax, and 3 charred (presumably human) bodies. The Key of Sezrekan is now free for the taking again.
This leaves a mystery as to the identity of the charred remains, and what did Vathek actually do to incur this sorcerous result? Clues will point to the trio of corpses to NOT be Vathek or his companions.
Beneath the Well of Brass wrote:
The Key of Sezrekan is an infamous grimoire bound in demon-flash and inscribed on plated of hammered gold.
The sheaves of chaos are rendered in Hyperborian and confer damning, caustic knowledge of the universe to any daring to study its pages.
With a DC15 Intelligence check, a character is able to apprehend the first plate:
a primer on mastering the uncaring powers of Chaos. Comprehension of this single plate is sufficient to allow a 0-level human (with sufficient XP) to advance as a wizard, acquiring their first spells.
Later plates build upon prior concepts, with subsequent sheaves requiring a cumulative +5 DC per page.
Mystics, initiates, black magicians, and their ilk who devote time to study the plates can reduce the DC of any one plate by 1 point for each week of study.
The nature of the subsequent panels is left to the judge's discretion. Perhaps the grimoire is seeded with the true names of diabolic powers, hints and clues for later quests, or even the means of reaching Lost Agharta or fabled Sagar-Matha.
List of Spells in the Key of Sezrekan (my additions courtesy of Purple Sorcerer):
Ekim's Mystical Mask (1st), Force Manipulation (1st), Mending (1st), Patron Bond (1st), Sleep (1st), Detect Invisible (2nd), Shatter (2nd), Slow (3rd), Sword Magic (3rd), Write Magic (3rd), Sezrekan Patron Taint, Invoke Patron (1st), Sequester (1st level Patron spell), Shield Maiden (2nd level Patron spell), Phylactery of the Soul (3rd level Patron spell).
Samuel the Orphan (Jim) would have an initial DC15 chance to advance as a wizard, but since he's already declared this, I'd allow a bonus for class level and Intelligence mods to his check.
At this point, he would have access to five 1st level spells to choose his four 1st spells from. He would not be able to decipher the higher level spells identities or effects without further study.
If he desires other spells not here, I reveal that
"Later plates build upon prior concepts, with subsequent sheaves requiring a cumulative +5 DC per page. Mystics, initiates, black magicians, and their ilk who devote time to study the plates can reduce the DC of any one plate by 1 point for each week of study."
Study the book and roll against the DC20 check to learn one new spell of his choice. Of course, I want to limit these choices to the Quickstarts, since I have three of them now, and let the players use them at the table while we learn the game. I have two Core rule books, which I allow a player to look up from time to time.
Once we are more comfortable with the system, I'll allow players to choose spells (wizard and clerical) from the Core rulebook.
Every time Samuel the Orphan (Jim) wants to learn a new 1st level spell from the Key, its a DC20 check, 2nd level spells is a DC25 check, 3rd level = DC30, etc. -1 for every week of study and another -1 for every wizard level.
To delve deeper into the Key and learn of its dark secrets, its a DC25 or higher. I haven't a clue as to what to put in it that would be appropriate.