Universom is a roleplaying game rule system created by french publisher Siroz Productions for its first games. The goal was to have a common ruleset for many different science-fiction games, to help production and game design and allow players to move quickly from one game to an other.
Four games using the Universom system were released: Berlin XVIII first edition, Whog Shrog, Silrin and Koros. Each contained the Universom system, with their own setting-specific rules added.
The Universom system is rather simple: characters are defined by stats between 1 and 20, and percentage-based skills. Skills scores depend on stat scores and points added by the player at character creation. Actions are resolved by rolling percentile dice under the appropriate skill.