All Things Share One Ancestor, and the Survivors Rule

Long, long ago, a certain being tossed a few fish fry into a pond. When that being looked at the pond again, it found that those few fish fry had given rise to countless species and billions of descendants! Some of their descendants stayed in the water, some crawled ashore, and some even took to the skies! Intrigued, the being decided to speed up the evolution of the fish fry's descendants and see what these species were capable of. And so began a battle for evolution and survival that swept across every species on Earth! Birds, beasts, and humans slaughtered one another in all kinds of extreme environments. One in a hundred would be chosen, again and again, through countless cycles. Only those who remained at the end would be allowed to keep living! Strength, intelligence, and luck were all essential in these harsh environments. The strong preyed on the weak, and only the fittest survived. Only the last one left alive could evolve into the strongest! We all share a common ancestor. The harshest environments shaped what we are today! We set out from the same starting point and made it all the way here. The road was littered with corpses, and we were simply the ones left standing! But in the struggle for survival, the last one standing is king. As long as I make it to the end, I will be the one and only king of this world!