From publisher blurb:
This is Codex Sanguine II! The Codex Sanguine is an expansion for the Immortal Blood Supplement. Immortal Blood presents a new take on Vampires for Pathfinder 1st Edition, specifically within the Aedrenar Campaign Setting. The Rules in Immortal Blood deconstruct the original vampire template, and add a seventh new ability score that Vampires can be increased overtime. As this ability score increases, these Vampires gain more strength and new powers (some of which are only found in this rules system.)
Even if you don't plan to play Aedrenar, any setting that has Vampires as a core focus can benefit from the Codex Sanguine and Immortal Blood. Specifically, the Codex Sanguine offers new Blood Powers and feats for Vampires to take!