Jadeite
Jadeite was the first of Queen Beryl's generals. Jadeite used a different way to capture energy. He would disguise himself as different people. Once he dressed as a sea captain to capture energy. While doing so, he fell in love with a photographer. (which happened to be Usagi at the time). She also began to like the captain too, but soon realised it was Jadeite. She turned into Sailormoon and foiled his plans.
His goal was to capture energy, he wasn't very successful but did find out Sailormoon's true identity. He tried to tell Beryl about his findings but she didn't want to hear his excuses so she killed him instantly. She then warned the others that if they failed like him, they would die like him.