From Underground

A third-party monster manual for Old-School Essentials and other old-school fantasy role-playing games, featuring creatures and factions that dwell underground. Its entries include fungal trolls, cave-haunting spirits, a criminal gang of floating eyeballs, and a cult devoted to a flaming green skull, with details and hooks for use in adventures.

基于属性/数值（STR、CON、PER 等）等级制（获得经验值并升级）职业制（飞行员、巫师、科学家等）