(Please keep in mind that this is coming from someone that has never played any of the games, only watched the anime and read the manga)
Not going to lie, volume 3 was a huge letdown. After waiting over a year for it to finally come out, we don't get to see the other girls really fight, our epic showdown is really just another "I know you're a good person at heart, we're the same!" shouting match, and the whole thing was a rush job.
Watch the opening scene in the anime, the one where Asuka is on her training mission. The action in that scene is what we should have gotten at the end in the manga, but it just wasn't.
Worse, the first two books make it seem like we're going to get an interesting story about infiltration, betrayal, and ninja tactics mixed in with loads of fan service. I liked that Hibari almost seemed to be the main character, and that the story was going to be more about her conflict first. Then I thought we'd get more stories about the other girls.
Instead, it feels like the final version used the handbrake to make a hard right and ended up wrecking the car.
Am I clearly thinking and being too critical of a manga that is based on a fan service fighting game? Yes. But that's why I felt so let down by volume 3. The first two had potential to be more than just "We're ninjas and our boobs can crush your head" but the third one did not deliver. I've heard that this happened because it was cancelled so they had to rush, which just makes it more of a shame.