Grimoire of Souls

The Grimoire of Souls is an item.

This black-coated, dusty tome is protected by a thick buckle sealed with wax mixed with blood. A barely noticeable humming emanates from the spine. Despite the name, no souls are actually trapped within the book. Instead, the pages are inscribed with mystical images and words that strengthen and toughen the reader's soul - which of course extends to the body as well. Anyone studying the arcane diagrams and runes for a full day finds himself suffused with the book's power. Afterward, the material inside the book vanishes, leaving the pages empty. A given individual may benefit for no more than one of these grimoires in his lifetime.