Sentinels of Peace: Curse of the Ruby Ring — Author Unknown

For three thousand years, the Sentinels of Peace have been protectors of world peace. Four young heroes have been chosen to carry out the task-Cooper, Solange, Koen, and Ori. Summoned to help save Emperor Hiroshi Ishikawa's empire from ruin, the four sentinels, each with unique and supernatural abilities, are tested and must work together to beat back the evil sorcerer Shinigami.