In the first arc, the group battles the Dark Kingdom. Led by Queen Beryl, a team of generals—the Four Kings of Heaven (四天王, Shiten'ō, lit. "Four Heavenly Kings")—attempt to find the Silver Crystal and free an imprisoned, evil entity called Queen Metaria. Usagi and her team discover that in their previous lives they were members of the ancient Moon Kingdom in a period of time called the Silver Millennium. The Dark Kingdom waged war against them, resulting in the destruction of the Moon Kingdom. Its ruler Queen Serenity later sent her daughter Princess Serenity, her protectors the Sailor Soldiers, their feline advisers Luna and Artemis, and the princess's true love Prince Endymion into the future to be reborn through the power of the Silver Crystal. The team recognizes Usagi as the reincarnated Serenity and Mamoru as Endymion. The Soldiers kill the Four Kings, who turn out to have been Endymion's guardians who defected in their past lives. In a final confrontation with the Dark Kingdom, Minako kills Queen Beryl; she and the other Soldiers then sacrifice their lives in an attempt to destroy Queen Metaria. Using the Silver Crystal, Usagi defeats Metaria and resurrects her friends.