Disclaimer: I do not own Star Wars.
Anyway, this is mostly from theories.
1. Kylo Ren is a double agent in a way.
2. Force-bonded.
3. Snoke is Darth Plagueis.
Keep in mind:
1. Ben Solo had always been, since childhood, enticed by Snoke to the Dark side.
Then I have a bombshell theory, don't think its anything at all credible though. But if you're a Kylo Ren/Ben Solo fan, maybe you'd like it. Haha!
In the End.
Background:
The Resistance has defeated the First Order. And in the First Order's final breath, Rey stands on the ashes of Darth Plagueis, finally killing him after having chased him down from hiding. He had been heavily wounded in their previous battle. Spent, she looks around and finds death everywhere, in the lifeless bodies around her, the debris, the rupturing base. And although the ground she stood on shook and trembled, soon to burst into that empty void in the universe, she succumbs to the pains in her body.
. . . .
It was the end; the last moment, the final and inevitable fragment of the war.
And Rey, spent, bruised, and bleeding, cast her weary eyes down; her calloused hand releasing its grip on her worn-out saber. With a final breath, the instant her four-year old lightsaber hit the floor, she lost consciousness and crumbled to the cold, stained white floor. Her mind blank; void of the bellowing turmoil of the exploding First Order base.
She had thought, as she laid unconscious, accepting of her demise; that she would have fought the infamous Kylo Ren in an inevitable final battle between the Light and the Dark side of the Force. She had thought it was fate that they should face each other at the height of the war. But, her consciousness drifting back, blinding her with faint bursts of light, he chose to keep away from her. And, her chest muddled, unsettled with the agony of not knowing why.
Rey.
His voice, her mind hazy, was calling to her. As if in a dream, just as those many times before.
Where was he? She asked foggily herself, unwittingly stretching the question to Kylo Ren through the Force.
Wake up.
She almost smirked to herself.
I am awake. Her subconscious answered back.
Get out of here. Leave. The masked vigilante forced.
At this, Rey found herself distancing, and her mind answered back in accepting grim.
There is nowhere, no place I would want to go. She said, her mind unknowingly recollecting the dream she once had, a memory of the young untainted Ben Solo basking blissfully in the warm presence of his family. The vision had been a mistake, a quick lapse in judgment of the man struggling between the two sides of the Force. Yet, the recollection made its damage. Rey saw the memory. And it served as a crutch that stuck into Rey's consciousness, to the character Rey attributed to the cold, temperamental and deadly commander of the First Order. Fighting Kylo Ren was a personal battle of returning Ben Solo to the Light. And in the end of the war, in her failure to have done so, she welcomed the end. There would have been no greater feat than to return to General Organa her son. The boy that had looked back at her back then, the young parents that stared at her, an outsider to their joy, she failed them - all of them.
Unconscious, lifeless on the floor, tears fell from the corners of her eyes in torment.
I'm sorry. She thought, speaking to no one, not to Kylo Ren.
She could feel him through their connection. And she knew he was searching for her. Aching, she forced herself to return to her throbbing body and pushed herself from the floor. Looking before her, she saw Kylo Ren standing on the other end of the bridge..
She could feel his anger simmering behind his mask, infuriated at the sight of her.
She was resigned to die, even if it be through Kylo Ren's saber. She had nothing more to give the Resistance, no spirit left to shell out. They would let her rest after this battle, in that eternal peace. In this demise of the First Order, she would die with Kylo Ren.
The commander of the dying First Order was fast approaching. His pace was quick as he continued to advance to her, unarmed and rash as he bellowed.
"Get out of here!"
Rey only glared at him from where she sat.
"I have never been afraid of you, Kylo Ren!" She spat as she summoned her lightsaber. "Nor am I now!" As she saw the masked man walk to her, consumed with hatred, she took to her feet and focused on the Force, emptying herself of her bodily pain. This was it, she thought, determined. If she couldn't save him, she would have to kill him.
It was then that she was suddenly shoved back with a blow from the Force. Groaning as she tried to pick herself up, her head heavy and swelling in the pain of her wounds, she looked up to find Kylo Ren removing his mask and his eyes facing her glinting with irrational anger.
"You could've had it! You could've joined us!" Rey heatedly cried out to him. "The First Order's destruction was inevitable! You disrupted the balance!"
Suddenly, she is pulled up and painfully raised by her clothes, the grip of Kylo Ren - choking.
"This is the end." She bit at him, no longer caring about the outcome of his rage. Nothing would come of anything he was to do now. The First Order was finished. Darth Plagueis is dead.
It was then that she was forced to lose consciousness, falling limp into Kylo Ren's arms.
Let go of me. She cries in her head, realizing where he was taking her. You will release me!
In the cries of death and the explosions throughout the system, she wakes from unconsciousness just as she is shoved into an escape pod. Her eyes, shinning with a rage that equaled Kylo Ren's, shot to the man by the latch, his face now emptied from the anger on him before and replaced with a hard, blank expression as he looked back into her heated glare.
Suddenly, she realizes, as he walks out of the pod, that he wasn't just helping her flee. He, Kylo Ren, had made the conscious decision to die with the First Order.
It was in that instant, in his final moment, that he removed from his person his true mask, his cold expression, his tough exterior. And, his eyes - Rey, torn and confused, forced herself towards him, in a great ache for answers - softened, and with his deep voice, unmistakably lighter, kinder, said.
"I," Rey's jaw clenched in the growing agony of realization. "I saved you." He finished, eyes shinning with a sliver of all he's had to hide behind this mask of Kylo Ren. The questions you have always asked, I have always known the answer to. In his eyes was the haunting image of the man she had never known, the man who she never knew kept her alive, the son of the man she considered closest to being her father - Ben Solo.
"No." She shook her head, pressing her hands to the sides of her throbbing head in disbelief, in realization, in pain. The question that has never left her, that had always reigned in her curiosity. The question of her identity, of the reason she survived the massacre, of the reason why she was left in Jakku. The man before her took a step back - and Rey continued to cry, "Don't!" She pleaded as he reached for the lever dispatching the pod. "Please," She begged, trying to stand, to reach out to him. "DON'T!"
And, with a final glance, Kylo Ren - Ben Solo turned to her with a smile that was apologetic, sad, yet thankful, pressed on the disengager which closed her pod and shot her away from the dying First Order base, away from death and away from him, her savior, her knight - the singlemost person who held all the answers to the questions she had.
Goodbye. He bid. And in that same instant, Rey lost his presence in the Force.
Her eyes stinging with hot tears, she tried to hold herself, keep herself from shaking as she recollected all that has happened in the past five years and made sense of Kylo Ren's confession. And slowly, she would later realize that the commander of the First Order had a hand in every success of the Resistance.
"There is Light in him." General Organa once told her. "I can feel it."
THE END.
Summary: Rey is ready to die, thinking she's done her part in bringing balance to the Force. By this time, a lot of people have died, maybe even Luke. She's a Jedi master here already. So, she kills of Plagueis and is heavy injured. Sensing she was resolved to die, Kylo blows up. He had planned for Rey to follow through with what his grandfather had started, what Luke continued, allowing the Jedi to bring order to the galaxy. Kylo was a necessary evil needed to quell the horrid intentions of Darth Plagueis. So, he saves her and stays behind, fully knowing that his continued presence in the galaxy was of no good purpose for its recuperation. He tells Rey it had always been him, he was the person she has always been waiting for to return to her in Jakku. Her friend from infancy, her partner in the Force.
So, that's basically my theory - working off from The Empire Strikes Back.
Just simple, from one of the flashbacks of Rey, the ship she sees leaving her in Jakku has red tail lights? Anyway, it emanated the color red. The red outline/contouring similar to the big ship owned by Han Solo and Chewbacca when they first meet. When I first saw it, I immediately thought it was an enemy ship, like one of the First Order? Only outdated, maybe like from more than ten years ago.
Plus, Rey's flashbacks of being before the Knights of Ren, as in looking right in front of them. Why was she not killed? Someone she knew must've prevented it. Maybe Luke? Not really, they were more or less ambushed, the Knights of Ren, even if unable to beat Jedi master Luke, would've and could've certainly killed the child Rey.
Plus, Kylo's anger at hearing that a girl was helping BB-8. That hints to him knowing of a girl specifically living in Jakku.
Plus, all the theories out there that Kylo Ren knows Rey's identity and saved her or something.
Well, anyway, so my theory or I admit myself to the theory that it's Kylo Ren who leaves her in Jakku, saved her from the massacre, and is ultimately good. Also, it has a very Vader feel. Anyway, just all fun and games. Looking forward to VIII.
Anyway, I have overused my break time. Will edit later.