He flung out a hand, jumped backwards immediately, stung into a response. 'Don't,' he yelped, his other hand flying to his hip to retrieve his own blade.

She flipped the handle open smoothly, feeling the call of the dark side, leashed but powerful under her hands. She raised the weapon into an opening stance, her finger resting on the toggle that would switch it on.

'Don't,' he repeated. 'I can explain.'

She span the hilt, testing its range. 'I'm not interested.'

'You must be,' he countered. 'Or I'd already be dead.'

'The only reason you aren't dead is because I keep giving you second chances. You keep making mistakes and I keep letting you off. This – ' she waved the handle at him, 'will make sure I don't do it again.' This time, he was going to pay for his crimes.

He straightened, took a deep breath. 'I love you,' he said.

Anger cracked the dam she'd put up around her emotions, anger, burning white hot in her guts, bright and pure. These were the words she'd heard in the dark, this was the confession he hadn't meant for her ears, this was why she'd woken in the morning after spending the night with him with no regrets, no remorse – because he'd said this to himself, and she knew it was only a matter of time before he said it to her. He stood facing her and his black eyes were enormous, full of the emotions swelling his heart and his mouth trembled as if he wasn't sure quite what he'd just said but was determined to press on anyway. The rage she felt was beyond anything she'd ever experienced, and in that moment, for that fraction of time, she knew what it felt like to hate.

She switched on the Sith blade. The man in front of her took an involuntarily step backwards, his eyes widening in shock.

'Fight it, Rey,' he blurted, jumping clumsily away from her first stroke. 'You don't want to do this.'

She simply grinned at him, the power luscious in her veins, and scrutinised his movements carefully for an opening.

He dropped into a defensive crouch, igniting his weapon and the words came pouring out of his mouth, although she had no wish to say anything in return. 'I love you. You know that. And you love me.'

She went for him in a whirl of dancing blades, chunking the air into blocks of red.

His footwork was excellent and he manoeuvred easily out of her way, returning to circle her carefully, his mouth continuing to spout nonsense.

'I never imagined you would, not once. I offered you everything I had and you turned me down. I never thought that you'd see me as any more than a monster and I couldn't live with that. I tried, I spent a whole year trying, but when you got in touch after my mother died and I saw you again I realised I couldn't carry on repressing it. I tracked down my grandfather because there had to be a reason he was sending me visions of you. Turning you to the dark side was the only way I could imagine we'd ever be together. I was grieving and angry and I wasn't thinking straight so I went along with what he suggested at first but the more I saw you the harder it became.'

She tested his guard with a few flicks of her weapon, and he parried without seeming effort. She would have to attempt something more unexpected if she was to succeed.

'Everything changed when we spent the day together. When you were fighting the Knights you were so good, I was proud of you. I was proud that they thought you were mine and I wanted it to be true so badly I would have done anything. But you said you were going to take my place and I realised I didn't want you to do that. I didn't want you ending up like me. And then you held the saberstaff you've got now and I saw who you'd become if you turned to the darkness and I knew I couldn't let that happen. I always thought I wanted you like that – like you are now – but I don't. This isn't you. This isn't the person who challenges me and teases me and lets me hold her when I want to. I hate who you've become.'

She swung the staff at him, a succession of short, sharp strikes designed to put him on edge and when he raised his saber to block the next blow in the sequence she dropped, pivoted smoothly and attempted to amputate his legs. He jumped, avoiding the shot without breaking a sweat and she frowned, pulling back and continuing to walk the circle.

'You said the dark side would make me love you and I saw then how stupid I'd been, how stupid I was being. I was trying to force you to love me – I had a whole stupid plan in which I'd drag you off to meet my grandfather and you'd suddenly be convinced into joining me, or terrified into joining me. It was ridiculous. Utterly ridiculous. I realised as we sat on that beach that I didn't want to do it. I didn't want to be that sort of person. I didn't want to force you into anything. I didn't want to make you into someone you're not just to suit me. I sat there and held you and I decided not to do any of it, no matter what the consequences were.'

She attempted a rush, a high jab to the shoulder coupled with a blast from her free hand to send him off balance, staggering back while she cut away his weapon but he anticipated the move and simply dodged. She fell back to the floor, cursing under her breath.

'We went back to your room and I sent the command to stand the fleet down, knowing that my grandfather would find out what I'd done and realise I'd betrayed him. The First Order would know I'd betrayed them, too. That was the turning point, that was when I decided to change. You showed me the way. You said that if we were together, the dark side couldn't tell us what to do. No one would expect me to kneel, no one would make me crawl. I could just leave everything behind and as long as I had you, it would all be alright.'

She was getting tired of the flapping of his mouth. For the third time she engaged him, using the longer reach of her staff to get inside his defences, battering at him with all the speed and skill she could muster. He didn't seem phased. He didn't let her in. She was losing this fight – nothing she did appeared to make a dent on his composure and he would not stop talking.

'But you had to come to me. It had to be your choice. You had to want me as much as I wanted you or it wouldn't be real. So I walked away from your room, and I would have left altogether if you hadn't called me back. We wouldn't be here now if you hadn't felt something deep down, something that you didn't want to let go. It's still in there, Rey. You can fight this. This isn't who you are. You love me. You just need to remember that.'

The dark side in Rey was thirsting for blood. It was impatient with this lack of action, with the tedious conversation, with the thrust and parry, lunge and block. The dark side didn't want to hurt, it wanted to kill, to slash and maim and leave this enemy mortally damaged – there must be a way around the restrictions of the connection between them, a way to bypass the fact that neither one could kill the other. The dark side cared nothing for pain, pain made it stronger. It sought a way through, a way to make him drop his guard, a way to make him vulnerable and it found one. Rey grinned to herself, took a tighter hold on her saber in preparation for the final blow.

She said, 'I'm pregnant.'

The lightsaber dropped from his nerveless fingers and she whirled and stabbed him through the stomach with the end of her blade. For a second the pain in her guts was so acute it forced her to her knees, so sharp she couldn't breathe, couldn't think, as all the agony her enemy was experiencing was routed directly into her body through their link. Then the darkness rushed in and she recognised it for what it was, not a side at all, not an allegiance but an integral part of herself, one that swallowed the pain and reforged it as a weapon. She felt it locking around her, bolstering her defences, sealing her resolve and any shred of compassion she might have felt towards the man slumped at her feet was lost in the roar of hatred as she celebrated victory. Then she broke the bond and left him in the wreckage.

She felt a strange reluctance to turn the weapon off when she snapped back into being in the cabin of her transport a few seconds later. It had become a soothing presence in her hand and she found it hard to remember a time without it. The darkness spoke in her head and it blotted out all other concerns, with the certainty that she knew what she was doing, that she should follow orders and everything would be alright.

But it was going to be impossible to pilot the ship with a lightsaber in one hand so reluctantly she disarmed the blade but kept the staff open, propping it along the top of the flight console where she could reach out and touch it any time she felt the need. Without the red surety of the double ended beams her head felt fuzzy, less focused. She couldn't quite remember what she'd just been doing but the lightsaber was right there in front of her so it was safe to assume she'd been in a fight, or at least preparing for one. She didn't appear to be out of breath though, and there was no blood on her clothes, no sign of injury so whatever fight she'd been in she'd clearly won.

Her hands rested on the controls and she shook her head to clear it. Where was she supposed to be? There was a gap in her mind where whatever mission she was on should be, but the memory slipped out of her grasp. Every time she'd used the saberstaff before, Ben had been with her and without him to ask she had no way of knowing what had happened. He was not Ben, she reminded herself sternly, she did not know Ben. She remembered what had happened before she landed though, she'd been searching for the Supreme Leader, keen to find him and make him face her summary justice, make him atone for his lies.

Her fingers sped over the controls as she ran the scan. There was a First Order ship, the command shuttle in fact, on the smashed remains of an older structure somewhere out in the water but there were no life signs within a reasonable distance, which suggested that he had landed and then gone somewhere else, presumably through the Force. She didn't remember visiting the shuttle before so she plotted a course to land beside it, setting the craft down delicately on top of the metal platform in the middle of the waves.

The white hull gleamed in the ocean spray, rivulets of salt water running off its sides. The ramp was down but the ship itself was obviously empty, the engines switched off and already cold; it had stood there for some time. She crept up the ramp cautiously, just in case there was something hiding that she'd missed but nothing jumped out at her, nothing stopped her sneaking in and she didn't need to use either of the weapons on her belt. Step by step she made her way past the scarred walls, the ruined consoles until she reached the drawer in which he kept his treasures – two remained, the wayfinder and the helmet. She brushed her fingers lightly over the top of the latter, wondering whether or not to trigger it again, wondering what choice she should make.

Two courses of action suggested themselves. She could wait for Ren to come back from wherever it was he'd gone, or she could take the opportunity offered by his abandoned shuttle and its convenient map and go in search of the ghost who had poisoned her mind, the man in the shadows of Exegol. She took a moment to consider, and then hooked the wayfinder into the console, drawing the navigational input directly from its star charts. She would have far more chance of landing on a planet surrounded by Star Destroyers in the command shuttle than she'd have in a Resistance transport. This might be the only opportunity she'd get to launch an attack with the element of surprise.

As Kef Bir receded into a distant speck, she found herself reaching for the Sith saber with no very clear reason as to why. She wasn't under threat, no one was going to attack her in this disguise but she felt uneasy, off balance; her mind no longer felt like it was entirely her own. A nagging suspicion in the back of her head told her something was wrong, but a blanket had been drawn across her emotions and it was hard to poke through. She had arrived on the moon with her guard up, choosing to feel nothing but a justifiable desire for retribution, but even that feeling had been muffled somehow. She rested the saberstaff in her lap, drawing from it some measure of comfort. This was the right choice, she felt, playing with the curve of its handle, the smooth sweep of the opening mechanism, she should go to Exegol, she should confront the dark side. This was her destiny.

The journey was still a lengthy one, despite the speed of the ship and its many comforts. With the controls on autopilot she drifted from panel to panel, console to console, seat to seat, unable to settle, searching for something she couldn't quite put her finger on. This was the chair she'd sat on to watch the holocron that first time. This was the mirror in which she'd seen her reflection after donning the black dress he'd enjoyed so much. This was not her ship, but it was scattered with her memories, older memories which mocked her with the loss of their newer counterparts. The sense that something was wrong expanded, spread through her body until every part of her was restless.

The landing sequence finally indicated that it was ready to begin and she discovered that a stable bubble of breathable atmosphere existed beneath the overhanging slab which protected the entrance to Vader's underground lair. She exited the craft cautiously, her feet stirring up dust on the exposed plain, the ground rocky and uneven beneath her feet. The blue glow of her lightsaber did little to cut the darkness, or illuminate much of the path down the steep staircase she'd seen on Hux's recording. There was only one way to go so she took the path carefully, one hand braced on the rock wall to her left hand, eyes scanning for threats. Arriving at the bottom of the stairs she realised Hux hadn't filmed the various catacombs and chambers which ringed the central throne room as he'd never turned around. With the bridge across the pit in front of her Rey found a warren of openings at her back, dimly lit cloning pods standing prominently in some, medical apparatus she didn't recognise in others. From everywhere came a soft murmuring which the recording had totally missed; it sounded as if the very cave walls were alive, whispering to themselves in the darkness.

Rey followed the path that Hux had taken, crossing the chasm with tentative paces, lightsaber extended. As she passed through the gloom a series of statues appeared on the other side, six life size figures standing silent and unmoving, the dim light glinting off their metal bodies. It was only when she reached the other side and stepped back onto solid ground that she realised the figures weren't statues at all, but men. At least five men, she thought with a sour twist of her mouth, and one woman. A few paces more and she stood in the centre of the semi circle they had formed around her, but rather than preparing for combat as she was expecting, instead the Knights of Ren, moving as a single entity, dropped to their knees. It was a homage, a tribute and Rey's heart fluttered in her chest as she realised what it meant.

Their loyalty was given to only one leader, and the only way to become that leader was to kill the previous holder of the title. That meant that Kylo Ren was dead, and Rey herself now commanded in his place. She had killed Ben. That was what she couldn't remember, that was what had felt so wrong. Her resolve faltered for a second. She could remember nothing about the circumstances of his death, what they might have been doing at the time, what he might have said. Without thinking, her hand fell to the Sith blade, yanking it off her belt. This weapon was the only thing that could put such holes in her head and she felt a flash of anger towards it – she had wanted to hurt Ben as he had hurt her, but she had never considered killing him, it should have been impossible.

The realisation that he was dead dropped the centre from her world, he had been the counterpoint to her life for so long now she wasn't sure what to do without him. Although he had betrayed her in the worst way possible, let her down after convincing her to trust him, whether she liked it or not, he had always been her other half, the darkness to her light and the fact that that balance was now missing left her unsteady. She wasn't sure who she was if she didn't define herself against him.

She cocked her arm, preparing to throw the offending saber into the pit, but a noise behind her halted her in her tracks.

'At last,' came a voice that she recognised from Hux's bodycam recording. 'My daughter has come home.'

She lowered her arm, flipped open the case so that she was now carrying a weapon in each hand and sought the speaker. The Knights of Ren moved into a protective position to flank her and in a reverse that made her feel instantly guilty, she was glad both of their presence, and their single minded devotion to their leader. They would not fall under the pall of whoever waited in the darkness.

'I am daughter of no one,' she corrected, grateful for the first time that this was the case.

The shadows seemed to thicken in front of her and she could see the difficulty that the previous visitors to this cave had had. With the impenetrable blackness shot through with blinding lightning at regular intervals, her eyes found it nearly impossible to adjust to the darkness. She simply could not see the face of the man in the shadows and every time she tried a sudden shot of light would send echoes of itself across her vision for a few moments, effectively preventing her from focusing.

'And you are alone. This is… unexpected.' The disappointment in the old man's words was apparent.

'Kylo Ren is dead. I killed him myself.'

'Impossible.' The word snapped out of the shadows. 'Your bond is unbreakable. A dyad in the Force cannot be sundered by either party on a whim – you cannot kill him, just as he cannot kill you. You are bound together, in both life and death.'

She gestured behind her, moving forward so that she was at the bottom of the raised dais, the empty throne to her left hand, addressing whatever it was that spoke from the shadows. 'The Knights of Ren would beg to disagree.'

A snort of derision split the silence. 'They are limited individuals with a limited view. Death is not always permanent, as I am living proof.'

She took another few steps forward, liking the turn of the conversation. 'How did you survive death, Lord Vader?'

'The dark side is more powerful than the light, as you already know. You bear a weapon that I have not seen for many years, a weapon which makes you stronger than that puny blade you cling to so desperately. Show it to me.'

The blue saber was flicked out of her hand faster than she could react and went skittering across the floor. Tension thickened the air. There was a rustle as the masked figure sat forward and the whispering in the cavern seemed to get louder. Rey held out the Sith saber, but she did not dare switch it on. Becoming the person who had murdered Ben Solo here, in the midst of the darkness was a risk she didn't want to take – she had the sense that if she pressed the switch, that was the last thing she would ever remember doing.

'I see the fear in your mind. You do not embrace the dark side as you should.'

Rey was stung into defiance. 'I have embraced the dark side quite a lot recently,' she snapped. 'At your suggestion.'

The man in the chair considered that for a while, and she wondered how much of her mind he was able to see. 'You have, my child. I see that you have. This saber has shown you who you truly are – you struck down your lover in a fit of hatred, ran him through in anger and left him to die slowly. That was a death the dyad could not prevent, a loophole you saw and exploited. This means my plans must change. I had thought to bring you both here together, to suck the life from your bond and use it to power my restoration but I see now that is unnecessary. You shall be my successor, a replacement for Snoke, more powerful than he ever was. Your path to the dark side is nearly complete. Submit to it again, and you will truly be mine.'

She pushed away the sudden nausea in her guts, fixating on the one part of that speech she'd really understood. 'This saber doesn't show me who I am. It makes me become something I'm not. I've only ever used it to understand how to fight the darkness, not turn to it.'

There was a chuckle. 'This weapon speaks to me, as it does to you. It spoke to you on Pasaana, although you did not recognise its call. No collection of crystal and wiring can make a person become something they are not, the inanimate metal of this saber does not change your essential character – the power of it simply reveals what is already there.' He paused to let that sink in. 'Darkness is in your nature. You have already killed the one you love. You are a fitting successor indeed.'

Rey refused to listen to any more of this poison with its slow drip, drip of truth into her ear. 'I didn't love him,' she muttered, casting about for anything with which to refute the suggestion laid at her door. 'And he didn't love me. He lied to me. You told him to. You told him to pretend to love me and that was why I hit him, it was justice, not hatred.'

The lascivious exhalation that followed these words crawled down her spine and made her feel dirty. 'I saw his mind. His feelings were not a pretence. You would not have taken the bait if you had not felt the truth of his words.' He sat back abruptly. 'But that is irrelevant. He fell to the light, but the mission I gave him has been achieved – you are here, my savage beauty, and you have walked the path to the dark side on your own.' The machinery surrounding him whirred as he advanced. 'Now take your rightful place at my side.'

There was a groaning noise from the stone on which she stood, and a shaking thrummed through the base of the throne as the giant legs which backed it juddered, and then clanked into life. As she watched the colossal structure came awake, stirring itself into slow and painful action and a hole opened in the base, extruding another piece of stone, upon which rested a twisted, deformed object which might have once have been a chair. The shadows parted, revealing the bent shape of an elderly man and the spider-legged throne reached out, manoeuvred the shape of its master onto the broad seat in the midst of the tangle of appendages.

Once settled, the hooded figure gestured at the vacant seat to his right hand. 'Come,' he said.

Rey wasn't listening. 'He fell to the light?'

'He need concern you no longer. You struck him down in cold blood, and earned your place at my side. Come, my daughter.'

'Your daughter is dead,' she answered with a bite of anger. 'I didn't strike him down, that saber struck him, not me.'

'You held the blade. The dark side runs in you far more strongly than it ever ran in him. He fought the light but you have never fought the darkness.' The man on the throne appeared to be swelling, puffing up with renewed strength, his volume increasing. 'He could never shake the attachment he had for his family, and he thought that in you, he had found a new home. How mistaken he was. You killed him for that mistake.'

'I didn't kill him,' Rey gritted out. 'I couldn't.'

A sigh cut through the shadows and for the second time in her life Rey felt a fierce push on her chest, a punch in the ribs over her heart, the physical manifestation of a remote dark side attack. 'Let us see….'

She did see. The amnesia holding back her memories of the three times she had held the Sith saber broke and she saw herself from an external point of view, gripping the weapon in her hand. She watched as this new Rey, this woman with the sharp cheekbones and dangerous eyes chased Ben from the command shuttle and had him cowering on the floor, as he slavered with admiration. She watched as he fought her hand to hand on the beach, saw her pinned down beneath him and cringed as she wrapped her legs over his thighs and offered him the gratification he was craving. She saw the dawning horror on his face, the disgust with which he regarded her, the guilt that drove him to levitate a rock and try to smash the dark side out of her head.

The third time was the worst. She heard the heartfelt apology he'd tried to make, understood the explanation she hadn't listed to, watched as the dark side consumed her, controlled her, turned her into its slave. He dropped his weapon, tears standing unshed in his eyes and she... she stabbed him through the stomach in what was clearly a mortal blow. She dropped to her knees with the pain and he was still reaching out for her, clutching at his wound but crawling over the floor in an attempt to reach her, to save her from herself. She left him to die. Only then did the fact of his death become real, only then did she feel what it was she had lost.

'You are my daughter. As everything of the dark side is mine. As Vader was mine, as Snoke was mine, as Kylo Ren was mine. The dark side bows to my will and I am its embodiment. Now take your rightful place and rule the galaxy at my side.'

Rey's head dropped. She wasn't the person she'd thought she was, and that wasn't because of her bloodline or her ancestry – life wasn't that simple. She'd murdered Ben, and not because she had a dark side grandfather lurking in her past, that was his excuse. She'd run a lightsaber through his guts because that was simply who she was, that was what she was capable of, all on her own. She'd been hurt and angry and she'd lashed out; knowing that the connection between them would prevent her from dealing an immediately fatal blow, she'd left him gravely injured and then flown away in his shuttle, preventing him from getting help. Ben was dead because of her. He'd tried to apologise and she'd ignored him, he'd tried to save her and she'd repaid him with blood and pain. She had struck down an unarmed man in anger and in hatred, in contravention of everything she'd ever been taught, disregarding all the tenets of the Jedi, every code of conduct the Resistance had ever held dear because underneath, that was who she was. Ben was dead because of her. The Knights knew it, and now she knew it too, and that made her fall complete.

She surrendered as the double bladed weapon hummed into incarnadine life without her fingers moving at all. This was her destiny. This was what she deserved. She didn't just have darkness within her, this was where she belonged. The world went blank. And then the dark side replaced it.

She was one with the Force, it moved within her like a lover, thick and powerful. 'Yes, my master,' she said, bowing her head.