If a Killer Doesn't Kill People, How Can He Find Out the Cause of Death of a Beautiful Girl?

Jos is a killer who travels from all walks of life and never fails in his mission. In a bar in a snowy town, a brown-haired girl shivered from the cold, got into his coat, and stuffed a mechanical eye into the palm of his hand. She is the target of Joss's mission. Then he saw her death image in advance in his eyeballs. He wanted to save her, but she died. Mission accomplished, he returned to his home world. "No, how are you alive?" (Suspense, romance, light science fiction, loop, multi-world travel)