'That isn't your grandfather?'

He didn't look down, his eyes locked on his adversary and one hand raised, becoming a focal point for the lightning trying to blast them away. 'When I realised you'd left the hotel with the Resistance I thought you'd need some time alone with them to explain. I also knew it was only a matter of time before the First Order staged a coup – and not that pathetic attempt by Hux – but I was more worried about the man who claimed to be family and his fleet. So I went to Endor, to the wreckage of the Death Star, the last place my grandfather had been alive and I searched the throne room for biological traces, biometrics, scans or records or anything that might help me identify who it was I'd met here, who it was who'd been sending me visions. Who it was I was up against.' He nodded at the skeletal figure blasting death from its fingertips. 'This is Emperor Palpatine. Or what's left of him after the Death Star blew up.'

Rey reached behind her and wound her fingers through his free hand. 'How is he still alive?'

'I don't know and I don't care. All that matters is that I kill him.' He squeezed her fingers although his attention was still focused on his enemy. 'This man destroyed my entire family. There would be no Darth Vader if not for him. I would not have become Kylo Ren. My grandfather died as Anakin Skywalker, and he was very clear to point that out when I finally met him. He didn't want me to become like him, he never spoke to me through his mask. Every voice I have ever heard inside my head has belonged to the Emperor, everything Snoke ever said was him, every time I thought my grandfather was showing me the darkness it was him. I am the man I am today because of him, and he's about to face the consequences of that.'

Rey squeezed his fingers back. 'You're not the man you are today because of him, but in spite of him. You're not Kylo Ren.'

'I don't think you are either, if it makes you feel any better. You asked the Knights to kill me and they went straight into a training drill instead – that's basically mutiny as far as they're concerned. You were in charge of them for all of five minutes – what did you say to make them dislike you so much?'

'Nothing. I only spoke to Ushar.'

'Hmmmm.' His thumb sneaked into the gap between their fingers and stroked her palm, a simple gesture of affection that made her lower lip wobble. 'Still jealous, I see.'

He was building up to something. This conversation was simply a delay while he worked himself up to a decision. She stood there holding his hand, chatting, while he used the power between them to block all the dark rage being flung their way but Rey had the distinct sense that he was preparing himself, although she wasn't quite sure for what.

She clutched at his hand, harder this time. 'Remember who you are,' she urged him. 'Don't give in to hate, that was where I went wrong.'

His smile was sad. 'I've managed to break everything I've ever touched. Now I'm going to make amends.'

He closed his eyes, and although they were still holding hands, she could tell he was putting as much distance between them as possible. There was a tug on the Force, a pull on the connection that bound them and Rey found the fluttering control that danced around when they touched dimming somehow, the raw power that he brought to the bond growing at the expense of her own contribution.

'Let me do it,' she whispered. 'I can control it better than you.'

His eyes opened again, and there was a light in them that wasn't usually there, the irises shading to gold. 'This is my fight now,' he said, although his lips didn't actually move.

The shield dropped and in the single instant of time before the Sith lightning burnt them to a cinder, Ben threw the full power of the Force bond at the Emperor, calling up every scrap of power that either of them had ever possessed. She felt the bond drain from her in a torrent and with it came a flood of memories, recollections that weren't her own as Ben flung every piece of himself at his enemy. She saw him through the failing connection, felt the fear and confusion of a little boy coming into his strength, the resentment and loneliness of the teenager sent away by his parents, the honed rage of the man he became, angry at everything and everyone, and at himself most of all. She saw how lost he had been, how solitary he was sealed away behind his mask, so hard on the outside, so miserable within. She saw the point at which he found the Sith holocron, the fascination he had felt for the woman in the image who had seemed to offer a way out of the mess he had made for himself, how his pursuit of her, when she was finally found, had led him to delve too deeply into her mind, too quickly, and had called out power that had always been hidden. In that moment, he had sealed his fate.

She saw the connection between them solidify, felt him begin to worm his way from under the weight of the darkness pushing him down the more they spoke, but then came her own face in Snoke's throne room rejecting his hand, rejecting the future he wanted so desperately and then she felt him tip over the edge again, back into the shadows. But he hadn't forgotten. He had spent a year longing for what might have been, sending out probe after probe, spy after spy to track her down, obsessively combing through Resistance broadcasts in the long hours of the night to find some trace of her, and then despising himself for this weakness. His mother died and the depth of his mourning shocked him, because he'd thought that all his tears had already been shed. Then Rey herself was back, and his yearning was so great he was willing to try anything to have her, sacrifice anything because he couldn't bear to lose her again. The depth of his love for her was frightening.

But he wasn't thinking about her any more. He picked up every emotion he'd ever had, brought them together and turned them into power. He had always been fierce, and passionate, and prone to excess and it was this he was using to fuel his attack, bashing away at all the painful memories he held as he had once hit his side in the snow to gain more strength. He couldn't carry on like this. Even as an observer Rey could feel that this use of power was too expensive, he was burning himself up in an attempt to destroy his opponent through sheer force alone. But power was nothing without control, and Ben wasn't drawing on her except as a power source. He was the engine, she was the pilot and without her he was going to crash.

There was a moment in which it seemed to be working though, in which the force of the lightning attacking them weakened and the wheezing of the mask became more apparent. Rey couldn't see the Emperor's face, but the conflagration gave more light and it was obvious that he was struggling, as his shoulders hunched and he retreated back onto the throne as he absorbed Ben's power. But then his fingers straightened, the bony digits strengthening and Ben's hand moved fractionally as he anticipated a renewed attack, with the shield he had placed around them reforming and the torrent of power diminishing in consequence. However, the Emperor did not shoot at the couple in front of him; to Rey's horror, he directed his bolts at the floor.

The cavern heaved as the lightning hit it, rolling and bucking as the stone reacted to being walloped dead on with dark side energy and the first tremors of an earthquake rippled through the rock. Rey staggered, steadied herself on Ben's hand and then the second quake hit, much stronger than the first, and the section of the floor on which she was standing abruptly raised high into the air, separating itself from the rest of the cave bed with a roar. She tried, but the seismic manoeuvring was too much even for her abilities to counteract and without quite knowing how it happened, she let go of Ben's hand. The earth shook, breaking itself into chunks in front of the throne and she fell, landing heavily on her hands and knees with ringing in her ears and the taste of dust in her mouth.

Ben had fared much worse. She spotted him through the gloom, a shuttle length away on the opposite side of the room, sprawled full length with a small pool of blood already gathering where his stomach wound had re-opened, trying to raise his head and failing. Ignoring her, the Emperor tottered forward, his steps doddering, the medical apparatus ripped from his face to reveal a puffy white visage, the skin sagging as if it had slid from his bones before the decay was arrested. He was moving slowly, barely on his feet, but his intentions were clear. Rey scrambled up, slipping on the loose rock now strewn all over the floor, scrabbling to reach Ben before his enemy had time to get there.

She was too late even before she set off. Poised for attack, the old man took up a position over the body of the younger one, who raised a hand weakly.

'Now you will die,' the Emperor intoned, lifting a single finger to propel Ben's limp form into the air. 'And the Empress will take her place on the throne. When she has birthed your children and I have raised them as my own, they will begin a new generation of Sith. Think on that, as you fall.'

Ben's eyes sought Rey but although his mouth moved, no words came. Instead, slowly, and carefully, as if he was putting all his remaining effort into the action, he smiled.

Then his body jerked and span head over heels as the Emperor threw him into the pit and Rey was left alone.

She had spoken to him too much about making amends. She stared at the empty air he'd occupied and that was the first thought that came into her mind. She'd tried to make him say sorry for what he'd done ages ago on that balcony on Dorumaa and he'd told her he'd make amends in his own way. Then she'd told him to apologise to Rose and she'd asked him to stand trial and he'd refused both of those options as well. She'd attempted to murder him as a way of forcing him to atone for lying to her and he'd dodged that too. But this was his way of paying back some of what he owed. He'd come to rescue her but that hadn't been his only aim. His plan had been to kill the Emperor or die trying, and he'd only succeeded in the second of those two objectives. The distance she'd felt from him, the decision he'd been preparing himself for, had been his way of saying goodbye.

He hadn't wanted her forgiveness, that had been clear since the first time they'd had sex, but only now did she realise why. He had fallen to the light, learned the error of his ways and decided for himself that the only way to achieve redemption was to sacrifice himself in the most meaningful way possible, by completing what his grandfather had started and bringing an end to the threat of the dark side.

Except that the dark side had fallen to its knees and was currently dragging itself across the floor towards the throne by its fingernails. Without the mechanical apparatus keeping him alive it seemed that the Emperor was only hanging on through sheer determination, Ben's attack having robbed him of the majority of his strength. Rey started towards him, flinging out her hand but the blue lightsaber had gone with Ben into the pit, or was buried under a pile of stone somewhere, and that wasn't the weapon that answered her call. Instead, the two halves of the broken Sith saber whizzed across the room, flying into her outstretched hands.

The Emperor raised his head, his blind, white eyes seeking the source of the noise and he sat up, his hands raising in preparation for another attack. It was an attack Rey knew she could not withstand on her own. Ben had drained the bond of much of its power but he wasn't around to complete the circuit anyway, so any reserves of energy which might still be left were inaccessible to her without the other half of the dyad. She was alone.

Luckily, she'd had a lot of experience in being alone, as Ben had reminded her only a few minutes ago and it failed to frighten her. Her lips tightened on a mirthless smile. He really did know her better than she thought. Despite the fact that she'd been holding a dark side saber and wearing a dark side crown it hadn't changed who she was – the woman who had once been alone, but who now belonged. As long as she remembered that lesson, this plan would work.

She dropped to her knees, held out the pieces and bowed her head. 'Forgive me, master,' she said.

The Emperor pushed himself upright, took a few shaky steps in her direction but his defensive pose didn't falter and he kept his hands raised. 'You betrayed me, apprentice.'

'Punish me, master,' she grovelled, placing the saber carefully on the floor and curling both arms deliberately over her belly. She had no idea if she really was pregnant, but the Emperor seemed to believe it and if he thought she might give birth to a new generation of Force wielding, dark side Skywalker children he would be less likely to terminate her.

His hands lowered fractionally. 'You will demonstrate your loyalty. Pick up your weapon.'

'Yes, master,' she promised, keeping her eyes on the broken pieces and noting the way they shimmered as the Force touched them, as the two halves melded themselves back together under the influence of the old man's mind.

She picked up the blades, and, under the silent threat of the fingers still pointing in her direction took a deep breath and turned them on. The dark side coagulated in her veins, drowning her senses, dripping into her thoughts and turning them black. But somewhere deep inside herself Rey did not forget who she was. The part of her that felt and did not think remained pure, untainted by the poison flooding her system. She held onto the certainty in her gut while shadow poured through her mind. She was not alone, not any more.

'You will eliminate the Knights of Ren,' came the order and she bowed her head.

'Yes, master.' He would think that the weapon controlled her because on every previous occasion it had, she had never fought the darkness – it had always made her its slave. No more. She rose to her feet demurely, took two paces past him, then whirled and sliced him in half with the red blades.

Palpatine fell with shock in his eyes and disbelief on his lips, the two halves slopping onto the rock floor with a disgusting smack of flesh, black mucus spilling out of his torso where blood should have been. He fell as if whatever it was that had been animating his body had been released, the body itself discarded, tumbling gracelessly to the floor without so much as a twitch, no last breath, no final words, no outstretched hand. But a wind roared through the chamber with the power of a tornado, and in its wake the whispering which had always hovered on the edge of hearing built into a shout.

Rey turned, seeking the source of the noise and for the first time noticed that the walls of the audience hall were not solid rock but made up of banks of seating, concealed in the darkness. In each of these seats sat a robed figure and each of them was cheering. She froze, unaware until now that she'd had an audience and dreading the moment in which this audience would realise that she'd killed the Emperor and move to attack. There were thousands of them, there was no way she could fight them all. But they didn't stop cheering. Some of them were on their feet, others waved their arms, still more began to clap. Then the room was full of it, thunderous applause, loud enough to bring the roof down if it continued much longer.

Still holding the saber, Rey's brain was sluggish but the dark side overlay on her thoughts gave her an insight into the reaction of the crowd. She too felt an echo of exultation at the sight of the fallen ruler, and a sense of the rightness of his death, how fitting it was that the old guard should pass and a new successor should rise. This was how it was for the Sith, she realised, the apprentice was supposed to surpass the master and take his place. Extinguishing her saberstaff, she reached out a hesitant hand and summoned the crown that Ben had tossed away. She raised it slowly and then, to tumultuous hollering from the stands, placed it firmly on her head.

With careful steps she ascended the dais, turned, and seated herself on the throne. The crowd went wild, their feet stamping on the stone so loudly that the walls of the chamber shook. In that moment Rey heard the call of the darkness as she had never heard it before, but it had lost the power to take over, the light spoke with a quiet, steady voice inside her and she listened to its words. Even here, although she was alone in the midst of the dark side, she knew that it would pass and she would find the place she belonged once again.

With that in mind, she crooked her finger at one of the six figures hovering in the shadows at the back of the throne, figures which had come slinking back at some stage during the past confrontation and were now skulking around, trying not to be noticed.

Ushar bowed her head, and said in her usual surly tone, 'Mistress.'

'Find Kylo Ren,' Rey ordered. 'And bring him to me.'

It was the best she could do under the circumstances. Without the audience she'd have dived into the pit headfirst in an attempt to find him, but she couldn't take on this many enemies and hope to survive. Besides, she was sitting on the Sith throne, and as far as she knew there was still a Sith fleet hovering above Exegol, a fleet which somebody was going to need to destroy. Alone, she didn't have the power to move so much as a single Star Destroyer, let alone find some cunning way to blow them all up so she was going to need help. Specifically, she was going to need help from the Resistance, whose bombers would be more than a day's journey away by now.

But how could she possibly get a message through to her allies, sitting as she was in the middle of her enemies? There were buttons on the arms of the throne marked in a language that her dark side brain helpfully recognised as Sith, and tapping on a few of them brought a fresh cracking noise and the ceiling above the throne split in two, the halves retracting with a painful mechanical whine to reveal the sky above, a sky studded with glittering ships, all mobilised and ready to attack.

Rey considered her options. In theory, she could take a short trip through the Force to find Poe and let him know she was ready to assist him in any raid he might want to plan, but in practice, with the Force bond depleted and the darkness hammering to get in around the edges of her resolve, travel was unlikely to be possible. She could send a coded long range message but the chances of that slipping unnoticed through the massed Sith technology now at her disposal were slim to none – she simply did not yet know these systems well enough to be able to crack them. She could always put out a galaxy wide message announcing her ascension, providing her location and giving everyone a decent period of time in which to mount a rebellion against her, but that would only confirm her friends' worst fears about which side of the conflict she was now on.

She toyed with the switches, unsure which course of action to take. Being Supreme Leader was hard, she wasn't sure how Ben had managed it this last year, all on his own, and his desire for her to join him suddenly took on a whole new dimension. She'd just determined on the galaxy wide broadcast when a warning signal sounded from the arm of the throne. Enemies were approaching.

She turned her eyes upwards, and with a spasm of fear in her gut she watched a First Order Star Destroyer hove into view in the upper atmosphere. As she watched it was joined by tens, then hundreds of others, supported by a bevy of smaller craft, flurrying around the massive ships like ants locating a corpse. The navy had arrived.

And Rey of Jakku, last of the Jedi, member of the Resistance, Empress of the galaxy, was now in charge of a fleet so powerful she could do absolutely anything she wanted. The dark side sang in her head. Voices she didn't recognise whispered to her in a dead language she had never heard spoken and the saberstaff grew warm in her hands. But still she heard the call to the light. And then, something more.

A call sign, a familiar code, a bright speck somewhere up in the heavens that she couldn't make out with the naked eye. She pressed a few buttons and a display appeared above her head, mapping out the outlines of the ships against an information chart detailing their names, weapons capabilities and complements. There it was, right next to the First Order flagship, a craft that shouldn't have been anywhere near an enemy vessel voluntarily, a ship that the First Order hated, and would never willingly have let so close. The Millennium Falcon. And it wasn't alone.

As she watched, the entire Resistance armada emerged from the hyperlane above Exegol and took up position facing the Imperial hordes, each of the smaller ships ranging itself next to a First Order Destroyer until the combined fleet stretched across the stars.

Rey took a moment to experience complete and absolute surprise, and then abandoned her fears about being discovered, opening a short range channel to Poe's X-Wing.

'Oh. Hi Rey,' the pilot answered after an uncharacteristically long period. 'How's the weather on Ahch-To?'

'Rainy.' Rey tried to spot his craft but with so many others on the radar it was impossible. 'What are you up to?'

'I'm a little busy at the moment, can I call you back in ten?'

His confidence was staggering. 'Is something going on? I felt a disturbance in the Force.'

The disturbance was right above her head, and Rey was pretty sure it would have disturbed anyone, Force or not.

'Sort of.' She didn't miss the smug tone in Poe's response. 'I'm sitting right above Exegol about to destroy the Sith fleet.'

'How?'

'The Resistance negotiated a truce with the First Order. Or maybe it was the other way around. Doesn't matter. Not long after you left we got word that Kylo Ren had mysteriously died in mysterious circumstances which I'm sure had nothing to do with you, and General Hux had taken over as Supreme Leader. He called me straight after, said that because he was expecting Ren to get murdered he'd taken steps to get rid of Pryde as well and now he was in charge he wanted to discuss our mutual enemy. The enemy of my enemy is my friend sort of thing. Hux reckoned the Emperor would try to take over, with Ren dead and you disappeared and he didn't want that happening. Hux has waited a long time for power, he's not going to give it up easily. He didn't have the resources to take down the Emperor himself, the Sith fleet is much too big, so we agreed to collaborate. Together we'll take down the fleet, blast Exegol into smithereens before the Emperor can escape and then we'll – hang on, I've got another call coming in…'

There was a crackling on the line and Poe turned his attention elsewhere. 'Yeah, I agree, doesn't look like they've primed their weapons so we've got less than a minute. Remember what I said Supreme Leader, go for the ventral cannons. We'll cover you.' There was more static as Poe switched channels again. 'Resistance armada – here we go. You have your positions, the First Order have extended their shields to cover us, but we need to engage the Sith Destroyers long enough for our Destroyers to target their cannons. May the Force be with us.' The crackling was back. 'Yeah, with you too. No, I'm not sure it works for your side, but what the hell.'

The line cut out and Rey's comms equipment was full of blinking lights, as the commanders of the Imperial fleet requested orders from their Emperor. She raised her head, conscious that the cheering in the hall had faded out and had now been replacing by suspicious muttering. Although she had spoken quietly, she was sure that her conversation with the Resistance had been intercepted, and she probably had moments left before the audience mustered enough courage to rebel. The minute they contacted the Sith fleet above a single well placed cannon shot would obliterate the throne room and her with it. Her final act as Empress was to re-route weapons controls from every Sith Destroyer to the throne itself, and then lock the controls with the most complex password she could come up with a short notice.

The she strode towards the pit. 'Ushar?'

The woman materialised out of the darkness at the edge of the chasm. 'No life signs, mistress. And no body either. We've been in to check.'

Rey considered that for a moment. Ben could float, she'd seen him do it on his flagship when they'd kissed, and she found it hard to believe that if he had gone into the pit awake he wouldn't have caught himself before the bottom and floated back up to continue the fight. But just to make sure she asked another question.

'Are there any vessels missing from the Exegol manifest? The First Order command shuttle, for example?'

'No, mistress. But no extra ships were recorded as landing after your arrival either. I don't think he came here in a shuttle.'

That made sense. If he had travelled to Exegol by tracking her through the Force that would explain the lack of a ship, and it would also explain why he wasn't in the pit. If he had been unconscious, maybe because he'd hit his head on the way down, then the bond would have broken, and he'd have ended up right back where he'd travelled from in the first place. She had only to go and find him. First though, she would need to leave Exegol, because the same rules applied to her, if she went to Ben through the Force right away, the minute the bond broke she'd be right back on Exegol again, although by then Poe would have blown it up and she'd find herself Empress of a floating pile of ash. She started for the command shuttle with a swing in her step and then stopped when she realised she was being followed.

The Knights of Ren froze the minute she turned her head, duty bound to obey her, but reluctant to do so.

'I don't want your service,' she clarified. 'I didn't earn it. Find someone else to be your master or better still, don't.'

None of them said anything, but the largest Knight nodded, and another shifted his sword in a way that might have meant he was grateful. Rey didn't care, hurrying across the ruined floor of the presence chamber and picking up speed until she hit the ramp of the command shuttle at a run. Priming the engines, she set a course as far away from the firefight above as she could manage and blasted off into open space, unnoticed by any of the Resistance or First Order vessels firing indiscriminately, or the Imperial ships attempting to defend themselves without their offensive weapons.

She set a course for Ahch-To, partly because that was where she was supposed to be, and partly because she needed a safe place to nurse Ben back to health. It was highly likely he was lying on a planet somewhere, maybe even back on Kef Bir, unconscious and bleeding from a stomach wound that she would need to try to heal. Pushing the shuttle to the limits of its capability she made the journey quickly and didn't even bother to lower the ramp when she landed, grabbing a few bacta patches from the medical supplies just in case and then thinking very hard about Ben, the way she'd felt when he put his arms around her that last time, like she was coming home.

It didn't work. The usual blur of travel failed to materialise and when she opened her eyes only the twisted insides of the shuttle met her confused stare. She focused again, screwing up her face in concentration, trying for an older memory, something more explicit. Again she opened her eyes to find herself still in the command shuttle, just behind the pilot's chair. She sifted quickly through her awareness of the Force, finding nothing amiss. She had never been able to sense whether Ben was alive or dead, which she'd put down to the strength of the bond between them, they were bound together in life or death, and just because he'd stopped breathing didn't mean she'd feel any different. The thought made her panic and she squeezed her eyes shut, trying once again to locate him, but her feet remained firmly in the same place and when she opened her eyes the shuttle mocked her disappointment.

She couldn't find him through the Force. The connection he'd shown her how to operate had shut down and without it she had no way to locate him. But the Force had always connected them, why would it choose this moment to stop? She had only felt this kind of absence once before, when she'd looked into the heart of things and found someone missing, and it had happened right here on Ahch-To. There could only be one reason that she couldn't reach Ben, and it was the same reason she hadn't been able to find Luke, more than a year ago.

Ben had closed himself off from the Force. He didn't want to be found.