Boy! That is some ancestry!
Everyone is in that boat. Great events (which often includes wars) have immediate impacts that ripple down through the centuries. People who had life plans truncated by early death don’t have descendants, for example, and their dearly beloveds marry others who do have them. Could be something smaller scale, such as a fatal car crash on the way home from prom, or some thrill seeker who dies falling off a mountain or asphyxiating in a cave.