I think of all the musclegirls I have created, Katie is my favorite. That's probably because I'm taking the time to develop her character. Together with Amber & Julian, Katie is my flagship story. It's now over 1100 pictures long, and it follows Katie from when she was ten to adulthood.
Katie's fascination for muscle building starts when, in the very first chapter of the story, she walks in on her dad being trained by a huge female bodybuilder who is much bigger than him. She's even wearing a t-shirt saying "strong is the new sexy". That slogan will stay with Katie forever, and after this moment she'll be hooked. For her next birthday, she'll ask her parents to be able to go to the gym.
Throughout the story, we will witness her muscle growth, her building up of martial arts skills, and her getting more and more assertive towards her father. And she grows a lot taller and heavier too.
But Katie is not the only one infatuated with her muscles: so is Nathan, a schoolmate who has an eye on her, and is turned on by strong girls like Katie. Nathan is a small guy and as time goes by and Katie grows, she towers over him more and more, and Nathan just loves it.

Katie is, at least to Nathan and at least so far, a gentle giantess. She's not a tormentor to him in the way that for instance Marjorie is to Julian. Although she knows that overpowering her boyfriend would be the easiest thing in the world, Katie is sweet and protective towards him, and gives him all the muscle flexing and lifting that he could ever want. Later, Katie's psyche will become a little bit more tormented, as she sees the example of her friend Angela, who is also a female bodybuilder. Angela is a few years older and has more experience. She'll inspire Katie.

If you love strong female bodybuilder girls, who are sweet and gentle, then Katie is maybe your dream girl, and you're definitely in for a treat with the story.