Natalia Kaminski is a freelance mercenary and bounty hunter who operates independently of the Mage’s Association and the Holy Church, taking contracts from both sides. She has succubus blood in her lineage, which grants her enhanced physical abilities and the capacity to absorb magical energy from others. She makes her living by intercepting targets wanted by the Association and reselling them at high prices. Natalia is pragmatic and hedonistic, described as someone willing to do anything for money and unable to hold onto savings. Her personal creed in her line of work is that, no matter the method, survival must be secured above all else. She has a pale, often expressionless appearance, with short gray or light blue hair and blue eyes.

Natalia first becomes important to the story when she rescues a young Kiritsugu Emiya from a collapsed lab on Alimango Island, after she had sold information about his father Noritaka’s research on vampires. She takes the boy in as her apprentice, teaching him magic, combat skills, and the harsh realities of the hunter profession. She does not treat him as an adopted child but rather as an assistant, and she maintains a teasing, sexually forward demeanor around him. Despite this, she never uses him for magical energy and develops genuine affection for him.

Her final mission involves hunting a Dead Apostle named Vorzak who has infected a passenger plane with demonic insects. Natalia successfully kills Vorzak and disposes of the insects in his luggage, but fails to notice that many more insects were hidden inside his body, and they quickly overrun the plane. To prevent the plane from landing and spreading the infection across Europe, Kiritsugu makes the choice to shoot down the aircraft with a rocket launcher, killing Natalia along with everyone else on board. In his final message to her, Kiritsugu acknowledges that she was the closest thing he had to a mother. Natalia accepts her death with calm and resignation, understanding the necessity of his choice. Her death becomes a formative trauma for Kiritsugu, reinforcing his belief that the greatest good requires sacrificing a few to save many.