One of the greater superheroes that your girlfriend liked were actually the Zodiac witches. Magical girl superheroines that could defeat evil monsters from Hell, with astronomy powers of the 12 zodiac constellations. Basically it was a 12 member group in the superhero would, so your girlfriend decided to choose which one.
The only one associated with Justice-Man, and Wolfman was the leader of the Zodiac Witches, Leo. The power that Leo possesses was cat taming, judging by how powerful the constellation of the lion was as they come out every time it is late April, and early May. Of course, seeing how your girlfriend had side classes in astrology, and knew which constellation was which in the zodiac files of the textbook she read, so she could tell which one's were going to occur on her birthday. So, your girlfriend decided to use that.