Amberstar

From the back of the box:

Thalion, the innovative developer of fantasy role playing games, presents AMPERSTAR, the follow up to the successful epic DRAGONFLIGHT. Part one of the AMBER trilogy is set One thousand years ago, when the world of Lyramion was almost destroyed by a mortal man. A man who had combined his mortal being with a demon lord; Lord Tarbos, God of chaos.

No one could match his power, until the twelve magicians, using the magical amberstar, cast a great spell, forever banishing Tarbos to the third moon of Lyramion. Now the danger has returned. The black magus Marmion is trying to free Tarbos from his eternal prison, and has commenced the long ritual. No one realises the great danger that threatens Lyramion, no one but you!