The Earth is various shades of brown and black, dirt and decay. The dark shades are broken up only by the coloration of non-living things, like the blue water Vision sometimes spots that hasn't yet been filled with decaying matter. Corpses lay in the open. Occasionally Vision cremates them, but mostly he floats by out of hope that somehow, despite all logic, the bloated remains will be more useful than ashes eventually. That, and the burning tires him both physically and emotionally after awhile.
The Earth and almost all its living inhabitants are dead. It fills Vision with grief. He can remember perfectly how alive the planet used to be. He remembers the struggles and victories off its wonderful people. They filled him with joy and he treasured being counted among them despite his metal flesh and inhuman ways.
A few escape the toxic gas lingering in the air. Bruce Banner shares his fate of being spared, though the human took it much less graciously than Vision did. He hides himself in libraries and labs, seeking a way to take his own life despite Hulk's unwillingness to join the rest of humanity. Thor had come in the middle of the death, tried to save who he could, then had to part when it grew too much for him. Vision recalls Wanda living longer than most. It was something about her magic that allowed her to live an extra week, but eventually the effort of fighting took its toll, and she too succumbed to eternal sleep. Although J.A.R.V.I.S still existed, to say he functioned was a stretch. He hibernated until he could be of use again, as if time could fix the death sentence humanity brought upon itself.
Yet Vision floats through the lifeless world. Maybe, he dreams, someone lived through it all. Humans are such a versatile species, and Dr. Banner proved it by surviving. He's sure somewhere there was some variation that let someone live. So, he searches.
He knew of this apocalypse since he came into being. He's beyond human, beyond machine. He had felt himself become himself, and like a baby knew how to cry, he had known that within the next ten years humanity would kill itself and also several other countless facts. The Mind Stone helped. It let him open his eyes and have everything within reach. He supposes that the humans would have known it as well, if they could look beyond themselves. Ultron had known. Perhaps not the specifics, but he had known humanity's fate.
Today he walks through a cave, curious to see if any of its aquatic inhabitants escaped the death. He illuminates the enclosed structure via light from his palm. He finds the color of the limestone structure to be a pleasant change from the monotony of the dark colors above. In the middle of the ground is a lake. Maybe, he thinks, somehow life survived deep down here so far away from the surface where the difference in environment raised different creatures.
The sound of water dripping from the ceiling into more water registers to his audio sensors, and he flips his vision from sensing light to sensing heat. The world turns blue. He shuts off the light, kneels next to the water, and searches, both with his sight and with his hands.
Once this water held fish that lost their eyes because no light would ever reach them. Vision marvels at the idea and the ingenuity of organic life. Their struggle to survive forces them to adapt and become more unique if they want their kind to survive.
At least it had. Vision's search finds only remnants of life. Even here, there is nothing but death.
It fills Vision with sorrow. Oh, what a waste to have so much beauty destroyed! He would cry if he could, if the gesture would be more genuine than mimicry.
He stands, switches his vision back to visible light, and brightens the cave once more. He will leave Earth soon. Staying here brings him nothing but sadness. Thor offered him a home on Asgard or to help him find one somewhere else, but Earth was where he was created. He doesn't want to leave it, not yet.
As he walks back up through the cave, he hears a thought in the corner of his mind. It's not his own; Vision detects that instantly. Before the thought has time to create its first syllable, his systems are swarming around it trying to figure out its source.
/Told you,/ the thought said. /Humans ruin everything./
The words do not come in a voice. Its composition is as familiar as his own thoughts: the exchange of data that produce a mechanical mind. The bubble of separate consciousness disappears just as quickly as it forms, but it's enough for the android to preform a brief analysis.
Ultron. The name brings memories rushing back. When he assimilated the other, he had planned for the creature to be locked away too deeply in himself to ever be able to be aware of time passing, much less forming a coherent thought to outside stimuli.
He decides to rope off that section of his programming until he examines it more thoroughly. A firm wall is set up between his own, more sensitive files and the area he stored the murderous machine's programming. He leaves the cave and flies away.
AN: I don't know. I felt like someone had to.
Dialogue in italics and between slashes are supposed to represent mental commutation.