"Ninja" Natalie may be one of the most formidable rookie competitors to join The Challenge. The LA native and professional rock climber gained notoriety on American Ninja Warrior as one of the first women to advance to the Los Angeles Finals. If her physical prowess wasn't enough, Ninja also holds a degree in neuroscience, which she will no doubt use to gain a mental edge on her competition. Though the prize money would be nice, Ninja's true motivation to win comes from her desire to push herself as a competitor. As such an intimidating force, she'll have to see if she can find a partner capable of keeping up with her intensity and athleticism.