There is a tale told around the campfire of a horrible age of despair ruled by vile bloodcasters. These ancient sorcerers specialized in dark magiks driven by darker vices. Unfortunately, their secrets were written in blood on pages of celestial vellum and bound in a grimoire none hope to find.
The Bloodcasting Grimoire – if a magic-user spends one week studying this evil tome he gains the knowledge of the ancient practice of bloodcasting. By sacrificing 2 hp per spell level, the magic-user may recast a spell already memorized for that day. The damage may not be healed by magic of any means. The book is unable to be destroyed without undertaking a major quest. It is considered evil but will command a high price from the right buyer.
This ability assumes that the Swords & Wizardry Complete healing rules are followed so that only 1 hp is regained with every day of uninterrupted rest.
This work was inspired by the standard magic casting rules from the great microlite20.