RUNAL

RUNAL aka is a role-playing game supplement that was written in Japanese language for the GURPS game rules. It was written by Shou Tomono and Group SNE, then first published in 1992. It was followed in 1994 by GURPS Youmayakou.
Over twenty novels of a series named have been published based upon GURPS Runal. 
The setting is a fantasy world named Runal that was strongly influenced from RuneQuest. There are seven mysterious Moons grant magic power to worshipers. 
The seven colors Moons are worshiped by various people as follows:
The Rhiado continent is the main land and focus of the game. The strongest nation is the Tor-Addness Empire which is modeled after the Tang Dynasty of China. Its state religion is the worship of the Blue Moon. The Toru-Addness Empire are disputing with neighboring countries which worship the Red Moon.
YUELL the sequel of GURPS Runal was released in 2005 as a supplement of GURPS 4th ed.