Just thought I'd post here about Katsuragi's little backstory that I just passed in the story, it also explains her expressive desire to get stronger. I'm not sure they'll cover it in the manga as they did do Ikaruga's (a little) but they didn't do Yagyuu's (which is in Yagyuu's thread). This is something that will happen soon in the manga's story (happens after Hibari gets back to Hanzou) if they cover it so highlight for spoiler if you don't mind.
Earlier on in the story whilst Katsuragi is training (after her defeat at the hands of Hikage iirc) she reminisces about a puppy she used to have called Choco. I don't think this was shown in the manga, however the mountain training that she did was shown in the Hebijou manga but I don't know if it detailed the whole candle thing in the game. Later on, whilst Hibari is having a chat with Kiriya about her taking the super secret hidden technique scroll and subsequent transfer to Hebijou because she's an idiot (I dislike Hibari, both her character and her fighting style/secret techniques), the other girls go for a walk. Katsuragi ends up in some place where she happens upon Choco. Choco beckons for Katsuragi to follow him/her, which she does and eventually ends up at a farm. There Katsuragi sees her mother and father. She explains (if I understood it correctly) that her parents were ninja who failed a mission, because of that they ran away. Due to shame and without telling Katsuragi I don't know, there was a lot of kanji. I think Katsuragi's desire for strength is so that she will be able to somehow clear her parents name. She doesn't go to meet her them instead vowing to get stronger and goes back to the school. It showed an interesting side to the always energetic, perverted Katsuragi that you always see. If anyone else has played the game and can add/correct then please do so. I'd love to have more of an understanding of it.