Flower of Obscenity

Natsume, the prodigious kunoichi of the Hidden Ninja Village, harbored a secret. Through her torture‑endurance training—bound and whipped again and again—she had come to discover a hidden pleasure in her own suffering.

One day she was assigned what should have been a simple mission: infiltrate a noble’s manor and gather proof of human trafficking. Yet what she witnessed inside was far more disturbing—the brutal “training” of sex slaves—followed by the advances of powerful, brutish men.
Caught between her duty and a burgeoning curiosity for the very masochistic delights she’d only ever imagined, Natsume found herself unable to resist their dark allure. Just once, she yielded to the men’s demands… and in that moment, crossed the line she’d trained her entire life to uphold.

(Source: Fanza, translated)

Note: Released at Comiket 93.