DISCLAIMER: I really don't own Halo or Terminator, or I would live in a mansion and devote my time to researching artificial intelligence instead of writing fanfiction in my basement.
A/N: Weird. I never thought these two fandoms would comprise my first complete crossover, but they did. I originally envisioned this as being told in a manner similar to Darren Aronofsky's "The Fountain" (having two similar but not directly related stories) but focusing solely on the parallels wasn't working. So I thought "well, the coincidences are there, might as well use them" and wrote this in a semi-normal manner. I don't think anybody's done this explanation of what happens to John Connor after the war, either, which makes me feel special.
REACH
It felt like ice was slipping into John's brain. He waited, until finally she spoke.
"Not a lot of room in here."
His grin was hidden behind his visor; it had been far too long since he had heard that voice. Quietly, so that only the AI could hear, he murmured "Your dad still selling tractors?"
FORWARD UNTO DAWN
He looked around the Forward Unto Dawn - or the half that he was in, at least. The other half, containing the Arbiter, had managed the jump into Slipspace.
"Looks like this is it," he said to Cortana. "Reminds me of earlier days."
"All of this has happened before," the AI replied. "Still think this is the way it should be?"
SERRANO POINT
John Connor sat next to Cameron, his cyborg protector, bodyguard...friend. He stared out at the battlefield that, hours earlier, had been filled with war.
"I think this is for the best," he said. "I was raised to be a soldier, you know? The protector of humanity." He snorted. "Now that humanity doesn't need protecting, I don't know what to do with myself."
Cameron glanced at him. "You could leave. Just...set up some sort of residence out in the desert, alone."
"Never alone," he told the cyborg. "I'll always have you. But no, I don't think so.
"I always thought it could only happen to other people," he said. "When the Resistance members came back with PTSD, jumping at the sight of toaster ovens...I never thought it would happen to me. I never thought I'd think of a battlefield as home. But now...now it seems natural, I guess. A war is where I was raised to be."
"Some people want you in government," Cameron stated.
John laughed drily. "Oh, I'd never work out in politics," he said. "God, can you imagine me in a suit and tie, arguing with a bunch of stuffy old folks? Nah, that's one battlefield I'm staying far away from. Leading people is one thing; governing is quite another."
Cameron turned her head. "If you're sure. All the technology has been set up."
John nodded. "I'm sure."
The cyborg lay down on the ground, turning her head to one side. John took a small utility knife and, with almost surgical care, sliced around her temple, exposing the chip in her skull.
"John," Cameron said suddenly, and he paused. "Thank you. For everything."
He popped the chip and palmed it before resealing her skull.
"You're welcome."
Footsteps alerted him to the approach of Major General Perry. "Is it done?" he asked in a low voice.
John nodded. "Got the thermite?"
Perry took a container of the powder and John sprinkled it over Cameron's body.
"Chip on its body?" asked Perry.
John felt the comforting weight of Cameron's "brain" in his pocket. "Yeah," he said. He took a magnesium flare and dropped it onto the recreation of Alison Young's body.
The deactivated Terminator went up in flames, casting a dull orange glow on the pair's faces.
"You know it had to be destroyed," said Perry. "So did it, for that matter. We couldn't risk having any trace of Skynet remain."
"I know," John said. "It was necessary." He turned and started walking into the desert before turning back for a half second. "Don't find me," he told the Major General, before striding off into the darkness.
When he had gotten roughly a mile away from where the remains of Cameron's body lay cooling in the desert air, he knelt down and dusted away a coating of sand. A metal box was buried beneath the earth. He grasped a handle carved into the box's surface and removed the lid.
Inside was the cryochamber - a dizzying array of chemicals and electronics that would keep him in stasis for approximately 525 years. He fitted Cameron's chip into a small slot built into the box, then closed the lid, plunging himself into darkness.
"Ready?" asked Cameron's disembodied voice, through speakers embedded in the box.
"Yeah. You're gonna want to change your name, mind you, just in case anyone remembers John Connor's favorite Terminator in five hundred years."
"I know." There was a pause. "Call me Cortana."
John laid back against strategically placed cushions.
"Cortana," he tested the name on his tongue. "I like it.
FORWARD UNTO DAWN
"Still think this is the way it should be?" asked Cortana.
"I do," the Master Chief (John-117, Demon, John Connor, John Baum - he had gotten far too many names to keep track of) replied. "Hey - maybe next war, there'll be even bigger guns."
"Boys," sighed Cortana. "Alright, prepping for stasis now."
The Master Chief relaxed in his MJOLNIR armor. "Wake me when you need me."
She would. He was the Protector of Humanity, and she was his AI.