This a rewrite of a magical item that appears in "Expedition to Castle Ravenloft". I came up with this modified version mostly because the original seems kind unbalanced. The original version as written, would seem to allow a Warlock the change the extra least invocation granted by the Codex at will.



The Codex Advocare is a tome that gives benefits to warlocks who
can use invocations.

Description: The book, 1 foot by 1 foot and about 1 inch
thick, is bound in red leather. It is held closed by a silver locked book clasp, with a tiny ruby skull where the lock should be, and written on the clasp in Infernal is the phrase: "Prove that you are a Warlock". The title is stamped in silver foil in Infernal on the cover, and the interior is inscribed with the descriptions of all manner of invocations, also written in infernal. The book doesn’t look any different when it is providing its benefit to whoever claims it.

Lore: Numerous copies of the book are know to exist.However, information about the book’s creation is sparse. Some scholars trace its origins to an infamous warlock; others firmly assert that there never was an original. (Knowledge [History or Arcana] DC 25)

Activation: The book must be opened and formally claimed in order
to gain its benefit. In order to open the book the warlock must direct an Eldritch Blast into the ruby(touch AC 1, and takes no damage from Eldritch Blast) on the clasp. Instructions for claiming the book are printed clearly on the flyleaf . The book can only have one claimant at any one time—the most recent claimant becomes the sole claimant. To claim the book,you must read the invocation descriptions from beginning to end (takes 8+1d6 hours) and then verbally claim the book. Once it is claimed the owner may make a Spellcraft or Use magic device check 1/day(a day = a period of 24 hours) vs. DC 15 + Invocation's effective spell level(Spell Craft), or a DC 20+ Invocation's effective spell level Use Magic Device check. If the check succeeds the books effect activates, else the book has no effect that day. The book's owner only retains the benefit granted by this item while the book is on their person. A warlock can only poses one claimed book at any given point in time.

Effect: You know one more least invocation than normal
(you must be able to use least invocations in order to be able
to utilize this ability).


Aura/Caster Level: Moderate necromancy. CL 11th.
Construction: Craft Wondrous Item, ability to use
invocations, 8,000 gp, 800 XP, 20 days.
Weight: —.
Price: 16,000 gp.