Master of Monsters is a turn-based strategy game with a hex-based grid. The goal of the game is to accrue resources with which to summon monsters of various levels of power, and have them conquer and occupy holdings across the map including those belonging to the enemy. It is functionally similar to SystemSoft's other major strategy franchise, Daisenryaku, only replacing the modern military theme with a fantasy one.
The game was originally released on the PC-9801 home computer in 1989, only in Japan. It would later be ported to other Japanese home computers as well as the PC Engine CD-ROM and the Sega Mega Drive. The Sega Mega Drive version, developed in 1991 by Opera House, saw a localized port for the American Sega Genesis courtesy of Renovation. Master of Monsters was followed by several sequels, one of which - Master of Monsters: Disciples of Gaia for PlayStation - was also localized.