I always know what to do, Cortana thought while the Chief used a Scattershot gun to blow the head off two Crawlers and a Knight.
No matter what happens, he'll live to fight another day.
The Librarian Cortana.
She…she told us about Mendicant Bias.
We need to tell the Chief.
Telling him now won't do us any good.
What do we do?
We…we could leave him a message.
How?
The chip.

As the Chief continued to fight she pulled back ever so slightly to study the infrastructure of her carrier chip.
I can encode the message so it will only play if his DNA touches it.
He'll have to turn the chip over to the UNSC for decommission but he should get the message before that.
Hurry Cortana. There isn't much time.

"Chief, if you're getting this message, I didn't make it." She paused momentarily, feeling the weight of her own words. "While we were on Requiem," she continued, "the Librarian told me something really important. The Mantle of Responsibility has to be found, and she has chosen you to be the one to find it. I believe this is why she altered your bio chemistry. I think there needs to be a specific set of genetic codes to access it properly.

I don't know what the Mantel is Chief but the Librarian hinted at something. Something from the distant past may be coming." Cortana hesitated and said, "From what the Librarian told me whoever they are…they can manipulate the fabric of space itself. I think this is urgent. You have to find the Mantle before anyone else.

Chief, you need to go back to the Ark and speak with Mendicant Bias, the AI who is in exile there. He is one of the few who can help you in your new mission. The Librarian said it would be exponentially more difficult to find the Mantle without his help."

Cortana hesitated. She couldn't leave the last message he would ever receive from her so impersonal. There was so much she wanted to tell him. "John…I'm sorry for everything that's happened. I'm sorry I can't go with you. There's so much I wish I could tell you, so much which has been left unsaid. I wish…" she stopped herself. "Good luck."

Cortana ended the message and made sure everything was in place.

The Chief came up to the last terminal and plugged her in. She ejected her rampant parts into the system and almost immediately the shield came down.

"And yet…still you fail," the Didact said turning on the Composer.
Here we go. We've got one shot to do this right.
She smiled at him knowingly.
Before John had a chance to pull the chip she manipulated the ship's infrastructure to push the chip back out before she derezzed the terminal.
"Cortana!" He screamed falling backwards. He got up and picked up the chip.
Perfect.

Even in the system Cortana could still talk to him via his HUD. "Prime the nuke! Save them. Destroy the Composer."

As she watched him get up and run a pang of sadness went through her.
I wish I could be in the suit with you John.
We made a promise once, and we intend to keep it.

She turned on the light bridge and made sure to keep it on so he could walk across to the Composer.
Hurry Chief!
Here comes the Didact.
Damn.
Did you think John could set off the nuke before disposing of him?
No.
"Come warrior," he said. "Have your resolution."

As Cortana predicted the Didact picked John up off the bridge using the same gravity device he used on Requiem.
It's funny how I'm most always right, she mused.
"So misguided," he said as he began to choke the Chief.
So predictable.
"Humanity's imprisonment, is a kindness."
Now! She said to herself.

As one all of her rampant parts moved and began to materialize on the light bridge.
"In that case, you won't mind if we return the favor," Cortana said smugly.
"Your compassion for Mankind is misplaced," he said angrily.
"I'm not doing this for Mankind," she said leaping towards to Didact. I'm doing this for him.

For the first time in a year she wasn't at war with herself. All of her was working together to do something no AI had ever done before.
It's truly amazing what I can actually accomplish.

Before long she had the Didact pinned down and his armor disabled. John was already running toward him with a grenade which he would plant in the Didact's chest.
Hurry John. I can't hold him forever.

As soon as the grenade was planted she let go and it exploded causing the Didact to fall off the edge and into the slip space rupture below.

The Chief hit the light bridge hard and he collapsed, grunting. She watched him painfully make his way to nuke.
The timing has to be absolutely perfect.

He activated it. Moving as fast as she could she sent the nuke flying toward the composer and folded the light bridge around the Chief making a bubble which would protect him from the explosion.

It had happened so fast the Chief was still crouched in the same position he had been in when he activated the nuke.

He stood up, confused and immediately called to her. "Cortana. Cortana do you read?"

Suddenly, she was nervous. This had been her plan all along but there was something extremely vulnerable in what she was about to do.
No. I need to do this. For me.
For him.
"Cortana come in," he called once more.

Be brave.

She stepped out of the light bridge making herself about a foot shorter than he was. Somehow it wouldn't be right if she was looking at him squarely in the eye.

He turned toward her. Even though Cortana was outside the suit his connection to the light bridge made her still able to read his vitals and when he recognized her, she saw his heart spike. She smiled at him. "How…?" He said in amazement.
"Oh, I'm the strangest thing you've seen all day?" She teased.
"But if we're here…"
"It worked. You did it. Just like you always do." She saw him look around.
"So how do we get out of here?"
She smiled a sad smile. Always the optimist. "I'm not coming with you this time."
"What?"
"Most of me is down there," she pointed with her head towards the floating debris of the Didact's vessel. "I only held back enough to get you off the ship."
"No. That's not- we go together," he said firmly.
"It's already done."
"I am NOT leaving you here," his voice breaking. Cortana felt his vitals spike. She was detecting fear, anxiety, and stress.
"John," she said passionately. She wished she could alleviate his distress and shield him from the pain she was inflicting.

Cortana felt something race through her circuits as she raised her hand up and gingerly dragged her fingers down a portion of John's chest armor. She closed her eyes blissfully. She could feel him. "I've waited so long to do that," she admitted.

He was trembling, struggling to maintain composure. "It was my job to take care of you," he said refusing to look at her.

She bent her head in such a way so he was forced to make eye contact with her. I wish I could see his face and look into those large eyes of his. There were few people who ever saw Spartan's out of armor and most of those who did became disconcerted with their faces and their enlarged iris'. "They're alien like," she had heard one person say.

Cortana felt the opposite. In her opinion the Spartan's large eyes were the most potent mark of the augmentation and in her opinion the only part about the process which was beautiful. If windows were eyes to the soul, then looking into the eyes of a Spartan meant you were seeing everything good about humanity. Their bravery, loyalty, how they sacrificed themselves, their patience, optimism. All of these things were John, and these were the reasons why she loved him.

"We were supposed to take care of each other," she reminded him. "And we did." He looked at her again.
"Cortana. Please," his tone was laced with emotion and sorrow.

Suddenly Cortana understood. She was important to him. More important than anyone else he had ever met, and quite possibly more than anyone else he would ever meet. The bond which they had formed was stronger than even she could have guessed. It wasn't just one sided as she had tried to convince herself of. No. It's mutual. Even Spartan augmentation can't stop what happens beneath the surface. It's why he could never accept my death and it's why he is begging me not to leave.

She knew that somewhere, in the depths of her Spartan (yes, HER Spartan) what anchored the bond between himself and her was love.

He couldn't explain it, express it, talk about it, or even act on it like normal people. If asked about it he would be confused and deny it believing with a clear conscious he had never experienced such an emotion. But it was there buried deep within him, and he was letting her see as much as he could show her in this moment, at the end.

For the first time Cortana felt peace. Perhaps this would be just the beginning for him. She could hope that someday he could come to terms with his humanity and would lead a full life.

Cortana felt the light bridge beginning to deteriorate. There wasn't much time. She reached out and touched him once more, needing to take that small piece of him with her into the void.

She backed up slowly, determined that his face would be the last thing she would ever see.
"Wait," he pleaded.
"Welcome home, John," she whispered.

Then she let go of her grip on life, and felt herself began to dissipate.

All was quiet, and all was peaceful as she slowly faded into blackness.

THE END.