Taimanin Asagi(2007)

Taimanin Asagi is an adult anime series following Asagi Igawa, a seasoned ninja warrior who believed her greatest enemy was vanquished for good. When a dark pact resurrects her arch-nemesis, he returns with a sinister mission: to destroy everything she holds dear. Her boyfriend, sister, and fellow shinobu become targets in his cruel campaign of revenge. As Asagi fights to protect those closest to her, she faces escalating threats that test both her combat skills and her resolve. The series blends action with mature themes as the protagonist confronts an enemy determined to break her through the suffering of others.