White Diamond must be the biggest threat in the three Diamonds look at her planets and compare with the other two, White diamond might also be a fusion idk but just look

http://vignette3.wikia.nocookie.net/steven-universe/images/1/19/Tumblr_o0l4bxxod91r82j2ro2_1280.gif/revision/latest/scale-to-width-down/180?cb=20160107144226 (Unsupported image host)
http://vignette4.wikia.nocookie.net/steven-universe/images/c/c0/Tumblr_o0l4bxxod91r82j2ro1_1280.gif/revision/latest/scale-to-width-down/180?cb=20160107144158 (Unsupported image host)
http://vignette1.wikia.nocookie.net/steven-universe/images/7/75/Tumblr_o0l4bxxod91r82j2ro3_1280.gif/revision/latest/scale-to-width-down/180?cb=20160107144337 (Unsupported image host)