Kristen Stewart and Kellan Lutz Arm Wrestle in Breaking Dawn 2

By Marla Lehner

06/14/2012 at 07:05 PM EDT

Kristen Stewart has spent four Twilight movies being protected by her supernatural pals – but now it's her turn to be strong.

In Breaking Dawn – Part 2 Stewart's clumsy Bella Swan finally turns into a fierce vampire. In this new picture – featured with nine other exclusive images on EW.com – Bella puts her undead strength to the test by arm wrestling Kellan Lutz's Emmet Cullen.

Making Bella what costar Taylor Lautner describes as a "super-sexy vampire who’s athletic and graceful" was a job Stewart took very seriously.

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"I knew every single version of vampire, and I took a little bit from everyone," she tells Entertainment Weekly in its cover story. "But I wanted her to be the best.”

Stewart, who plays opposite her real-life love Robert Pattinson, says during a scene in which she attacks a (fake) mountain lion, she really started to embrace her character's transformation.

"I ripped that mother to the ground!," she tells the magazine. "For the first time I was like, 'Wow, I’m, like, really playing a vampire now.'"