The system is an odd one, a motion which is found nowhere else in the multiverse. For nowhere else in the multiverse have three planets so equal in mass and volume been close enough to each other that they have all begun to orbit about each other. Their individual pulls so much the same that they all rotate at the same rate, and have begun to roll about a central point. That point full of darkness and magic, with the system's trash stirring itself sometimes in an attempt to pull itself together and form a new planet all its own.
And the star, the blinding blue star, far away from the triplets, bestowing on them its light and life. It is here that the differences between the sisters emerge…for one of them, one is a planet so perfect, so supportive of life. There is precisely enough water to support the growing and dying, the precise thickness and composition of air for carbon- or silicon-based life. Ice at the poles, with artful meanderings south and north.
And yet it is a desolate, empty place. For the planet spent so much time preparing itself, that it had nothing left over for life to take root. It is, in all bluntness, too perfect to spoil. So it spins about the emptiness, echoing the starsong, mourning the flatness of its plains, the depth of its seas, the soaring height of its mountains, the unexplored caverns within them. For it feels it will always be alone.
The second planet is a world full of ice and jungle. The air is thin and cannot hold heat, and the planet freezes over whenever it is too far from the single sun. But the air is thin and cannot reflect heat, and so when the ice melts and the world thaws, life explodes forth as from an open wound. The plants grow quickly, faster than they should, sucking up as much of the light as they can, flowering, fruiting, and dying all within the space of only a few days. And then again, and again, until the world freezes again from distance. Here, life has developed, but it is strange to the eyes of almost everyone. For what other race in the multiverse is so equally equipped for surviving in the extremes of cold and heat, for both life on or under solid sheets of ice miles thick and in jungle-forests changing almost faster than an eye can track?
And yet, these creatures survive just so, and well. They have not wasted time chasing after metals which might be found within the dirt of the world, for the ice they live under and within prevents them from going down so far. They are endlessly inventive, and have great strength and sharp claws to dig out holes in the ice for what little warmth they can find. They are endlessly adaptable, and care little when their homes melt and they must find new ones beneath the branches of the ever-sprouting trees.
The last planet is a planet that was ever against the idea of life. To spite it, it belched forth vapors into its own atmosphere, poisons which would catch the rain on fire, give water the power to eat stone. To spite life, it carved its oceans out with fire and death, and refused to let them fill again with water. To spite even the eternal advances of life, it thickened its atmosphere so far that the pressure of the air flattened the earth and held in so much heat as to burn nearly anything to cinders.
And yet it is the world most full of life. And it is angered for it, for the jungles which have taken over its unfired surfaces, for the creatures which crawl and fly through them, for the scum which festers in the very fires it created to drive life away. Again and again, it tries to drive life away from its surface, into the darkness and silence of space surrounding; again and again, it fails. It has allowed the creatures to dive underneath its crust to chase the ores within, hoping that they would build ships and fly to its sister, but they have not. They have remained where they are unwanted.
It is becoming ever clearer to this third planet that they will never leave. But it refuses to give up fighting against the life which has invaded it, and so it seeks ever for new ways to rid itself of infestation. Perhaps one day it will succeed.