Dragon’s Blood (Black Planet #1) by Belinda McBride

San Francisco hasn’t been the same since the Great Shake of ’08. On the ruins of Fisherman’s Wharf, a ramshackle city rises like a mushroom, a strange dichotomy of safety and corruption. In this forbidden city, a monster prowls the corridors and alleys, seeking the nanite-enhanced flesh and blood of underground cage fighters.

Detective Annie Tanaka once survived an encounter with the monster. The attack left her clinging to life and riddled with fear. Now the monster has returned, and he’s hunting in her territory. She’ll need every weapon in her arsenal to face this enemy and prevail.
Unfortunately for Annie, her mentor, a legendary fight master, hasn’t been seen in decades, and her unwilling partner is next on the monster’s menu. Annie soon realizes her real enemy is not the monster, but her own fear. And against that fear, Annie must stand alone.