This is the force giving power to Beryl and her Generals. It rules the Dark Kingdom of the Negaverse
It was the driing force in the attack on the Moon Kingdom, in the Silver Millenium. Before the Negavers could completely take over, Queen Serenity used the power of the Silver Crystal to thwart the invaders. All of the Negaverse was put to sleep.
When the Senshi were woken in the future, so was the Negaverse. Beryl plotted a plan to get the Silver Crystal to free the Negaforce.
In the final battle between Beryl and Princess Serena, the Negaforce gave up its power to take over Beryl's body. Beryl and the Negaforce were both defeated by the SIlver Crystal, for good.
*Note*: In the Japanese version, the Negaforce was known as Queen Metallia, and she really took over Beryl's body, not just giving Beryl it's power.
[ The Negaforce | Beryl | Prince Darien | Jedite | Nephlite | Zoisite | Malachite]