I wish you died in the womb!
~ Nikki Bella to Brie Bella

Nikki Bella is a WWE Diva, a former Divas Champion, and a cast member on Total Divas. She is one half of the Bella Twins with her sister, Brie Bella, and she is currently one of the lead villainesses in the divas division

Nikki had a brief run as a villainess in the weeks leading up to WrestleMania 25 in 2009, when she and her sister, Brie, were the objects of affection from dueling tag team champions Carlito & Primo and John Morrison & The Miz. In the angle, Brie remained with Carlito and Primo, while Nikki became a villainess and sided with Morrison and Miz. The twin sisters even faced off against each other in a one-on-one match for the first time ever on the March 30, 2009 edition of ECW. On that night, the villainous Nikki cheated to defeat Brie. After WrestleMania 25, Nikki's run as a villainess ended when she and Brie reunited.

Both Nikki and Brie would become villains on January 2011 when they attacked Gail Kim after catching her with Daniel Bryan, who they were both seducing for weeks. With the use of "Twin Magic" (switching with each other during matches), Nikki helped Brie become #1 Contender for the Divas Championship, which Brie won on April 11, 2011. Both Nikki and Brie would engage in feuds with Divas such as Eve Torres, Kelly Kelly, and Alicia Fox. Nikki abandoned her villainous ways for a brief while when she revealed that she was supporting then-SmackDown GM Theodore Long, while Brie was supporting then-Raw GM John Laurinaitis. After their brief dissension, Nikki reverted back to her evil persona and went on to defeat Beth Phoenix to win her first Divas Championship. Nikki lost the title to Layla six days later at Extreme Rules when their "Twin Magic" tactic failed. Both sisters were "fired" by Executive Administrator Eve Torres the next day.

Nikki, along with Brie, returned to WWE on March 11, 2013 and resumed her role as a villainess when she and Brie began feuding with The Funkadactyls (Naomi and Cameron). Nikki suffered an injury months later, but she and newcomer Eva Marie assisted Brie in her feud with Natalya entering SummerSlam. Nikki's run as a villainess ended when the entire cast of Total Divas banded together against AJ Lee after she cut a scathing promo against them on Raw.

At SummerSlam on August 17, 2014, Nikki entered and appeared to help her sister during her match against Stephanie McMahon. However, Nikki turned into a villainess and attacked Brie, which helped Stephanie defeat her in the ring. The next night on Raw, the evil Nikki explained her betrayal by accusing Brie of mistreating her throughout their entire lives and claiming that Brie was never there for her. When Brie confronted her in the ring, Nikki delivered a vicious slap to her sister and screamed that she would never forgive her, causing Brie to leave in tears. Nikki would spend weeks tormenting Brie by continuously claiming to be abused by her, and she was even awarded by Stephanie for her actions; receiving a Divas Championship opportunity at Night of Champions. At the event, Nikki was defeated by AJ Lee in a Triple Threat Match that also involved Paige. The next night on Raw, Nikki even demanded that Brie give up the Bella name; insisting that she's the only one worthy of the name. The feud between the sisters led to a grudge match at Hell In A Cell, which Nikki won. As a result, Brie had to act as Nikki's personal assistant for a month, and Nikki wasted no time forcing her sister to perform several menial tasks for her.

Nikki became #1 Contender for the Divas Championship by winning a Halloween Costume Battle Royal. She won the title from AJ Lee after Brie delivered a kiss to AJ to distract her. After the win, the Bellas were back together as villains and they feuded with AJ and Paige for several months. The feud came to a head at WrestleMania XXXI, where the Bellas were defeated by AJ and Paige. Both Bellas would become babyfaces due to Naomi becoming a villainess on April 13. The Bellas later became villainess again by using twin magic against Paige.

As a villainess, Nikki, like her sister, was very egotistical and would constantly bully the rest of the Divas. Her betrayal at SummerSlam also portrays Nikki as being self-serving, traitorous and cruel.