A lot of the dialogue is from the game as I wanted to fit into what already exists. It's rough, but let me know what you think... sorry about the length.
This begins just after Shepard has taken the heaven-elevator...
Child: Why are you here?
Shepard: *groggily* Wh-where am I?
Child: The Citadel. It is my home.
Shepard: Who are you?
Child: I am the Catalyst.
Shepard: I thought the Citadel was the Catalyst?
Child: No. The Citadel is simply a tool. One that has been reclaimed.
Shepard: I need to stop the Reapers. Do you know how to do that?
Child: The Reapers are mine. I control them. They are my solution.
Shepard: Solution? To what?
Child: Chaos. You bring it on yourselves. The created will always rebel against their creators. So it was with us. So will it be with you. But we found a way to stop that from happening. A way to restore order for the next cycle.
Shepard: By wiping out organic life? I don't understand...
Child: No. We harvest ADVANCED civilizations. Preserve them from their own mistakes. Leaving the younger ones alone. Just as we left your people alive the last time we were here.
Shepard: But you killed the rest...
Child: We helped them ascend. Preserved them in Reaper form. Saved them from their own creations.
Shepard: What creations? What are you talking about?
Child: The synthetic. The new child that is born of organics. The child that destroys everything.
Shepard: What?
Child: We were like you once. We flourished and spread throughout the galaxy. We unlocked the secrets of the universe. We could bend the very fabric of nature and time, leap the galaxy in a single stride, but even that was not enough. We searched for purpose, a reason for our existence....
Shepard: You were organics?
Child: We were children of the stars. Searching for where we fit into the pattern of the cosmos. And when we discovered the truth, it destroyed us.
Shepard: What truth?
Child: Organic life has no purpose. We are an accident.
Shepard: An accident...
Child: We were a simple pattern. Basic chemistry combining into unusual chaotic forms. When we mastered the galaxy we found there was nothing else remaining. We were lords over a domain that had no need for us.
Shepard: That... but, why kill us? I don't understand! You found the edge and now you're punishing us for it?!
Child: No. We are saving you. Our children, our synthetic creations, did not suffer our qualms. They did not need to find purpose, they were created by us. We had given purpose to them. And that gave them the power to choose to rebel.
Shepard: You were beaten by your machines?
Child: You have seen the pattern yourself. The Geth. Your Rogue AI's. Even now, the pattern is repeating. As it did with us. As it always does. The war threatened to destroy everything. Our own weapons could wipe out suns, harness the dark energy of the universe that bound it together. We could have destroyed the galaxy.... we nearly did.
Shepard: The relay network....
Child: Our weapons. We realized that if the synthetics defeated us, they would not stop. All life, however simple, however small, would be destroyed. Eventually they would spread to other galaxies. They were infinite, could last indefinitely. And then the great accident, the great miracle of life, would be doomed.
Shepard: But you found a way to stop them! We're still here! Just tell me how!
Child: We became them.
Shepard: What?
Child: We could not defeat the synthetics. Not as we were, frail, mortal... flawed. So we evolved. Preserved ourselves as those you know as Reapers. We ascended.
We became the synthesis of life and machine. And we destroyed our children.
Shepard: But why all THIS?
Child: Our time was over. We knew we had reached the crucible of our existence. But we will not allow those who followed in our footsteps to repeat our mistakes. You will create your own destroyers, if you are allowed, and doom ALL life again. We do not give you that chance.
Shepard: But you're not saving us! You're dooming us!
Child: No. We are preserving you. You use our technology, spread through the galaxy using the Mass Relays, never learning the secrets for yourselves. Thus we confine you to this galaxy, so that we may preserve you. We divide you, cripple you from within. Turn your own forms against you. Contain your mistakes. Then, we allow you to ascend to become one of us, and thus, safeguard the next cycle.
Shepard: We don't WANT to be preserved! We want to keep our own form.
Child: You cannot.
Shepard: The defining characteristic of organic life is that we make our own choices. Take that away, and we become no better than the machines you claim to protect us from. We can choose not to repeat the pattern.
Child: You have already repeated it. The geth are only the first step. And even now, they have risen to a state of being that will allow them to destroy you, should they choose.
Shepard: They are standing beside us. We still have a choice.
Child: Yes. You have more choice than you deserve. The fact that you are standing here proves that. Despite all our plans, you have found a way around them. There is no certainty that another cycle will not do the same. The solution is....flawed. And then there is the Crucible. It has changed things. Created new possibilities.
Shepard: I don't understand. What does it do? How does it work?
Child: We could rewrite the stars in our time. The Catalyst was our greatest achievement, a machine that could alter mass and rearrange matter at will. The Crucible focus's that. Takes what it is given and allows the Citadel to spread it. But I cannot control it so I cannot make that happen.
Shepard: Make what happen?
Child: What you came here to do. You can destroy us, if you like. Wipe out all synthetic life in the galaxy, including the Geth. Even you are partly synthetic. It will give them time to find a new solution....But your children WILL repeat the chaos.
Shepard: But the Reapers will be destroyed?
Child: Yes. You may also use it to control the Reapers.
Shepard: So, the Illusive man was right...
Child: Yes, but he could not control us, for we already controlled him. The catalyst will let you merge with them. But it will destroy you, consume you utterly.
Shepard: But the Reapers WILL obey me?
Child: Yes.... We will do as you will. But without us, the pattern will reappear. And you will eventually choose for us to begin the cycle again, this time perfected. There is however, a third option.
Shepard: Which is?
Child: Synthesis. You are partly synthetic. Merge with the Catalyst and you can change all life in the galaxy to become as you are. As we are. Synthetic and Organic. The entire galaxy will ascend.
Shepard: The...whole Galaxy? That's impossible.
Child: Is it? You have seen it already. It is how we are able to combat you, fusing your forms with synthetic matter to create new DNA. You call them 'husks'.
Shepard: But...the whole galaxy....
Child: Everything in the universe is energy. Matter, mass, even time is nothing more than that. The Relays and Catalyst are simply tools that control that energy. Life will be preserved. The growth will be stopped. And there will be peace.
Shepard: Why are you telling me this?
Child: You have done what no other organic has. You have proven that our solution can be overcome. We underestimated you before, thought of you as a mere inconvenience. But you are more than that. You have given us a new...perspective...Variables that we cannot forsee.
Shepard: The perspective that organics don't like being murdered? Something tells me you haven't been paying attention...
Child: We have eradicated eons of life. You have done what none of them could. We do not confess that lightly. Whichever you choose, once the energy from the Catalyst is unleashed, it will destroy the mass relays.
Shepard: But if we lose the relays... We'll have nothing. Whole civilizations will fall!
Child: That is a possibility.
Shepard: But... I don't... I can't....
Child: The paths are open, Shepard. You must choose.
*Shepard looks down at her bleeding side, then up at the raging battle above her head. We see ships of all sizes being shot down, Reapers crumbling under crushing fusillades of fire. You can now choose to go down one of the three paths. OR... you can wait...*
Shepard: I... can't make this choice...
Child: It is the choice you asked for. It is salvation.
Shepard: No matter what, it damns us! Without the relays we will lose everything!
Child: Perhaps.
*We see the battle raging on Earth, squad members we have saved, armies we have recruited, all fighting desperately against overwhelming odds. Shepard, looks to the Catalyst.*
Child: You have no other way Shepard. Your followers trust in you. Make your decision.
Shepard: They didn't trust me to destroy us! You can stop this! You can choose to call them off! Just leave!
Child: No. If you will not choose a new solution, the cycle will continue. We will simply... reassess, for the future.
Shepard: It doesn't have to be that way! You can still give us a chance!
Child: We cannot. Your followers trust you to save them. You cannot. Not as you wish. This fight is in vain. We are giving you a chance. One that is more than you deserve.
Shepard: I won't play God...
Child: Your friends are dying Shepard. *The boy turns into the Virmire casualty* I know you'll do whatever it takes to get us through this, skipper.
Shepard: Go to hell...
Child: *turns into Anderson* Come on child. This is what you're here for! This is how we win! We can't fight them conventionally, you know that!
Shepard: **** you! I won't! I've beaten your kind already!
*We see the battle raging above them, the massed fleets being obliterated on both sides*
Child: *morphs into Hackett* We threw everything we had at Sovereign, and that was just one Reaper.... We just can't stand up against them. Not even together.
Shepard: No! We've broken the pattern! We've allied with the Geth! We've unified our species! It doesn't have to happen again!
Child: *turning into LI* You know we can't do this. We can't come this far just to throw it away! We're dying out here!
*Shepard can now choose one of the three options OR gamble everything...*
Child: *Illusive Man* Don't throw away everything over your ideals! This is the only solution!
Shepard: *turning to the child* Oh my god... you're scared... aren't you?
Child: No.
*a Reaper above them is destroyed under a feirce volley of massed ships*
Shepard: Yes.... you are... You should have rolled over us by now.... But you didn't...
Child: We have been merely delayed. If we must, we will destroy you all. We have offered you salvation.
Shepard: No.... you offered me a way to stop the fighting. You've never faced something like this before... The Illusive Man knew how to beat you, knew he could disrupt your armies... that's why you attacked him. Indoctrinated him. He came up with another option, he just didn't know it. He he thought he'd found control.... but he really found out how to turn that into Chaos.
Child: *aloof* We held the power to rewrite the stars. We are perfected. We cannot be defeated. Choose.
Shepard: Bullshit. You're not perfected. You're MACHINES. Machines that sit on the edge of the galaxy, lurking where we can't find you when you're vulnerable. Vigil said it himself. That's why you USE us! Turn our own people into your armies! You can't beat us on your own!
Child: We are the salvation of all life. We have swept away all before us. We will do so again.
Shepard: By blindsiding your targets through the Citadel! By coercing us into a trap with the relays! You've always picked off your opponents independently! You used the same tactic with the Collectors! You've never had to stand and fight the combined might of a galaxy united!
Child: Your arrogance will only lead to your destruction. Choose.
Shepard: No. We killed Sovereign. We killed the Reaper at the collector base. We killed them on Rannoch, on Tuchanka, and down there! We stopped you from using the Alpha relay, and you're spread thin. The Illusive Man found out how to control your armies, disrupt your signal. That's why you attacked him, you were scared. We can beat you.
Child: Paltry victories.
Shepard: Maybe. But the combined might of the galaxy is holding you back. The Krogan and Turians on Palaven, the Quarians and GETH on Rannoch. And we'll do it, here, on Earth.
Child: We have given you fair solutions Shepard. Options to fix the system.
SHepard: No you've given me YOUR options. We've shown you we can win, and you're looking for a way out, a way to cripple us because you can't do it the way you used to. You failed at playing God and now you want me to wipe out your mistakes! Well I won't. I choose what we've ALWAYS chosen. I choose to take our damn chances.
Child: You would risk the eventual destruction of all life? Risk the future to the likes of the Geth? The Krogan? More like them will follow. Do you trust them?
Shepard: They put their trust in me to unify them. I trust them to finish the job.
Child: We thought you were different Shepard. We thought you would understand.
Shepard: Happy to disappoint.
*The child transforms into Harbringer*
Harbringer: So be it. Shepard. *then disappears*
*Shepard collapses*
Shepard: Admiral? Hackett? Anyone...
*we see the crews of multiple ships, the soldiers and charcaters fighting below all in the midst of hectic combat hearing Shepard's broadcast. What happens next is dependent on whether or not you have enough war assets/readiness to actually break the reapers here. If you don't the Reapers win, no questions asked, and the cycle remains unbroken.*
Shepard:... I don't know if you can hear me. But the Crucible is not an option... it won't save us... It won't bring us victory. I know a lot of our friends have died for this chance. But this isn't the end. We can beat them. You can beat them. They've always won by dividing us, turning each other against ourselves. But no longer. You CAN beat them. The ships next to you, the soldiers fighting by your side, can beat them. They aren't invulnerable. We beat them at Rannoch. We beat them at the Citadel. You can BEAT THEM NOW. You can break the back of the greatest threat the galaxy has ever known, because you, together, are the single greatest force this Galaxy has ever seen. Give them hell.
*The battle that follows is the epic conclusion, as Shepard watches, broken and bleeding, as everything he has put into this unified force throws itself at the Reapers. This is where all those decisions come to fruition. We want to see those War Assets fighting. The Destiny Ascension obliterating a Reaper with it's main gun before being swarmed over by Destroyers, the Geth armada pulling along side to save her. The Salarian STG calling in a biotic artillery strike on cluster of Reaper troops. Wrex and Garrus, on the front sharing a stern moment in cover, before nodding to each other, brothers in arms, before charging over the barricade. Back to back, they face down hordes of husks, Wrex shouting defiantly, "You think you can take our future!? You think YOU CAN TAKE MY CHILDREN?!"
We want to see the Quarian flotilla scrambling, all guns blazing, trying desperately to form a battleline, as one of the admirals quietly turns to their crew, signalling his ship all ahead full. "For the homeworld. Keela..." their words cut off as the live-ship rams a Reaper, exploding spectacularly and damaging two others. We want to see the Normandy frantically weaving through the wreckage, Joker and EDI yelling warnings to one another as the fleets explode around them. We want Tali leading a charge of Geth Primes against a Cannibal gun line. Rachni drones swarming over a Reaper Destroyer by the thousands, pulling it apart from the inside. We want to see Grunt wrestle a brute to the ground and unload his shotgun into his head.
Happy or sad, we just want to see those decisions play out. We want to see that what we did mattered. And as the battle unfolds, you are left with the Choice. Do you think you have enough? As Shepard bleeds out, watching all he/she loved go up in flames, do you take the risk? Provided you have enough manpower, can you break the back of the Reaper fleet, though at horrendous cost? Once the battle is over, and the truth of what the Illusive Man discovered is revealed, the remaining survivors get the word out that there is a way to disrupt the Reaper signal, scatter the Reaper armies. Or something*
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