Kunai Sins of Princess Kaguya

Four assassins have kidnapped a young girl and holding her for ransom or as bait. Whatever the reason Kunai intervenes to save the girl, which despite his heroics kinda hits home with him due to one of his daughters is around that age. But what if this is a setup for something worse! Also marks the third apppearance of Striker the most deadly unkillable assassin, what is his goal in this book and who hired him.