The Seven Great Youma (最強妖魔七人衆 Saikyō Yōma Shichininshū?) were originally generic shadows imprisoned into Crystals, which when combined create the Silver Crystal. These were introduced in the Rainbow Crystals Saga, which consisted of 10 episodes.
The Seven Great Youma were seven powerful monsters that served the Dark Kingdom. Queen Serenity sealed them away in seven different crystal fragments and sent them to earth to be reincarnated as normal humans.
In the present day, Zoisite was chosen by Queen Beryl to reawaken the Seven Great Youma and get the crystals that each one was in. One by one, each of the Seven Great Youma is awaken from their hosts and fought the Sailor Senshi. Sailor Moon's Moon Healing Escalation was used to restore the hosts to normal while destroying their Youma side.
Queen Beryl later manipulates Prince Endymion to capture the hosts of the Seven Great Youma in order to combine them into one powerful Monster. Before Prince Endymion gets to Rei's grandfather, Sailor Mercury destroys the crystal holding the other six hosts of the Seven Great Youma.
Below are the summaries, shadows, and victims of the crystals.
- Gesen a.k.a Crane Game Joe, Red Rainbow Crystal
- Boxy a.k.a The Priest, Orange Rainbow Crystal
- Bunbo a.k.a Ryo Urawa, Yellow Rainbow Crystal
- Binah a.k.a Yumemi Yumeno, Green Rainbow Crystal
- Rikoukeidar a.k.a Reika Nishimura, Blue Rainbow Crystal
- Jiji a.k.a Grandpa Hino, Indigo Rainbow Crystal
- Bakene a.k.a Rhett Butler, Violet Rainbow Crystal
- The Seven Great Youma are an anime exclusive group.