Jedite is the first Negaverse agent to be sent to earth. He tries to gather large amounts of 'human energy' for Queen Beryl. He is also repeatedly defeated by the Sailor Scouts. Jedite is put into an eternal frozen state by Queen Beryl when he fails to get rid of the Sailor Scouts.
Nephlite is sent by Queen Beryl to replace Jedite. He seems very elegant, and with his proper manner, infiltrates human society by posing as the rich playboy Maxfield Stanton. Nephlite singles out certain individuals and uses their energy for his evil Queen Beryl. As Maxfield, he soon becomes the object of a huge crush by Serena's friend Molly. Because of her affection, Neflite eventually tries to save her and is destroyed himself. 
Zoicite is the third of Queen Beryl's henchmen. She quickly moves into her Queen's favor after her plan to discredit Nephlite works. Her first strategy is to find the rainbow crystals that Nephlite couldn't find. Zoicite is extremely manipulative, and is constantly trying to win Queen Beryl's approval. But she is destroyed by the Queen after failing to destroy the Sailor Scouts and recover the crystals.
Malacite is the strongest of Beryl's troops to fight the scouts. He is very shrewd and cunning, and is always trying to defeat the Sailor Scouts single handed. At one point he nearly succeeds in turning the Scouts against each other. When Zoicite is destroyed for failing in her mission against the Sailor Scouts -- Malacite vows to destroy them. He kidnaps Tuxedo Mask and brainwashes him to turn against the Scouts. But his plan backfires when Queen Beryl starts to prefer Darien to him. 
Queen Beryl rules the Negaverse, an evil parallel dimension. Her goal is to accumulate human life energy, and the Emperium Silver Crystal -- both of which are needed to free the Negaforce (Queen Metallia). To form the Emperium Silver Crystal they must find all the Rainbow Crystals hidden inside various Earthlings. When the Queen's henchmen find and remove a crystal, it turns the host into an evil monster, which must be defeated by the Sailor Scouts.The Four Sisters of the NegaMoon