Shitennou

The Shitennou (四天王; meaning "Four Heavenly Kings") were the four loyal and faithfully devoted generals and bodyguards of Prince Endymion. When they were all possessed by Metalia's vast negative energy, they became evil and served Queen Beryl and the Dark Kingdom. The members were Jadeite, Nephrite, Zoisite, and Kunzite. Each of them were named after a different stone.

History
They were originally the guardians of Prince Endymion, like the Inner Senshi to Princess Serenity. Suspicious of The Moon and its constant surveillance of Earth, they often argued with their prince about it. Their suspicion led them to turn on the prince and turn to Beryl. Despite this, they still cared for their prince and were shocked by his death. They are still rivals but also care for each other and are shocked by each other's deaths. When the Silver Crystal appeared, it returned the dead Jadeite, Nephrite, and Zoisite to life and returned Kunzite's memories of the past. They then dissolved into stones bearing their name, as did Kunzite when he is later killed. They later speak to Mamoru through the stones, telling him how Metallia could be killed and to be happy. Mamoru kept these stones and called on their spirits for advice and guidance throughout the series.