From publisher blurb:
Bring Lair of Sword & Sorcery (LoSS) to the Original Roleplaying Rules and OSR (Old School Renaissance) games. This conversion booklet provides guidelines for playing in the World of Kartharka, where combat is more brutal, treasure is more precious, magic is very rare, and chaos rules.
Demihumans are rare and feared.
Wizards and Clerics now use spell points rather than knowing so many spells per day.
New Multi-Class: Your fighter or thief can also become a Sorcerer; they summon, command, and enslave spirits for their own uses.
New Spell Levels require both an increase in character level and special amulets.
Magic items are extremely rare, with most now simply being made of steel.
Convert monsters from LoSS quickly
LoSS templates (Story Flowchart, Story Background, Lair Outline, Lair Details, and mapping page) updated for OSR.
Note: Requires both the Lair of Sword & Sorcery rules, and the Original Roleplaying Rules or an OSR system.