Nagisa's alter ego is Cure Black (キュアブラック)?. She has a habit of saying "Unbelievable!!" (ありえな~い!!)? when she is upset, and also "Lucky!" (ラッキー!)? whenever things go her way; otherwise, she might say "Unlucky!" (アンラッキー!)?. Her other catchphrase (especially in the English dubs) is "Give me a break!" (勘弁して!)?