First appeared in Asimov's. Reprinted by Charles Ardai and Mike Ashley.
Protagonist stops time paradoxes from occurring. He feels something in his telling him who/what will cause the disturbance and takes them out himself, vigilante style. The question is "How reliable is our protagonist?" It's a smooth transition from one style to another.
Another Watt-Evans story mash-up is "Windwagon Smith and the Martians", which mixes Ray Bradbury, Edgar Rice Burroughs, and the American tall tale.