Extinction of the Human Race
The shattered, golden husk of the giant crumpled to the floor of the throne-room. Wires and mechanisms spilled out of gaping fissures in armor plates and some kind of oozing organic fluid spilled from some of the joints. Potus Clarke, emperor of the human race was at long last dead.
When the cacophony of battle had died away, the victorious soldiers of the Galactic Republic stood in silence, taking in the gravity of the moment. This war had lasted longer than the entirety of recorded history when the first humans left Earth to explore the stars. For 70000 years the Holy Empire of Man had terrorized the galaxy. A silent sigh of relief for generations long passed spread with the news across the mighty milky way.
What few realized, but became gradually apparent in the aftermath of the war was that it wasn't merely the end of that conflict. It wasn't only the end of an empire. It was the extinction of the human race. Humans, in their heyday, had been the most numerous and arguably the most powerful of the intelligent species in the galaxy, having passed up the Cielioids during the Empire's reign.
Sure there were many descendants of humankind still around, that's why nobody realized it right away. There were clones, cyborgs, mutants, robots, chimeras of every stripe. One group called the Children of the Earth had started out human, but through genetic engineering had hybridized themselves with animals from their home-world to the point where basically no human DNA remained. Many of the artificial intelligences in operation were cobbled together from the brain-scans of humans and other entities. In fact the commanding officer of that final battle had been created from some of the best strategic minds of human history as well as some of the greatest philosophers. Because it turns out that when you know why you are fighting, you have a better chance to succeed.
The Emperor and his final elite were the last beings in the galaxy to claim the name human. Of course they had first destroyed the meaning of the word. The higher one went in imperial society, the more gene-treatments, bio-enhancements and cybernetic implants one was allowed to use while claiming the ancestral name. Most of the lower ranks of civilians in the empire had assimilated into galactic society generations ago and none of their descendants claimed traditional humanity. Those who remained to the end were all ultra-loyalists and universally refused to be taken alive. When the analysis robots went over the shell of the emperor, no signs of organic life were found at all, yet he clung to that name. . . human to the end.
The name human had meant a lot of things to a lot of people over the millennia, not always good, and not always bad, but for a long stretch of history the human race had been the star of its own narrative, but now that was done and life carried on.