Concepts

 In a world where it's survival of the fittest, two people form an unlikely friendship. Person A is average in strength and speed. Forms friendship with Person B because Person B seems slower than Person A, so if the need comes, Person A can leave Person B behind for whoever is attacking. Person B is unclear how much strength they possess. They appear helpless and cute, the kind of person you'd want to protect. This is, of course, an act. Person B acts this way in the name of self-preservation, calling on others' protective instincts to have them fight on behalf of Person B.

 Put the main character in a dress, with long hair and heels. Make them interested in fashion, makeup and flowers. Then, make them fall in love with a girl. By the end of the story, reveal that the main character was a guy all along.