Narrator: Last time on Sonic X x Male Reader. In a last ditch effort to save the galaxy, Sonic and Company decided to use the mighty Master Emerald to attack the Metarex. The giant gem shattered, but Sonic sped through space and the blast created an opening for our heroes. Meanwhile, Y/n was struggling with his heart condition after his fight with Shadow, so Chaos suggested merging there power, which allowed Y/n to become Chaos Y/n. Just as Sonic rushed to confront Dark Oak, he found himself in a stick situation. Amy quickly flew in to free him, but was also trapped, that is until Y/n showed up to help her in her rescue. Now as Dark Oak begins his final transformation, Sonic and Y/n must find a way to win against the odds. Can they and their friends rally to stop the Metarex and their maniacal mission? Find out on Sonic X x Male Reader!

Flashback.

A younger Star was standing next to Galaxina who was holding a baby Cosmo and the other Seedrians watched.

Starla: So this is the only baby that can grow from the seeds, Galaxina?

Galaxina: Yes. None of the other seeds had any signs of life.

Daisy: If this keeps up, our clan won't last for long. What should we do?

Chrysanthemum: Earthia has been able to hang on for so long due to the fake planet egg, but as time goes on, I see she's definitely getting weaker. That's her last child.

Baby Cosmo began to cry, but Star lovingly caressed her check.

Star: It's okay, baby. Don't worry.

Baby Cosmo stopped crying and just gave a little smile.

Galaxina: (smile) Oh, I almost forgot we haven't given her a name yet

???: Cosmo.

They all turned to the giant tree who had Earthia's voice.

Earthia: Cosmo. She's the last of my offspring and the last hope for the galaxy. Guard and protect her. Our future depends on it.

Galaxina and Star looked to their younger sister.

Galaxina: Did you hear Mother? You're a very special baby!

Star: Don't worry, Mommy. I'll always protect my little sister.

Back to present.

Everyone was looking at the gaint, beating seed.

Amy: It looks so strange. What is that thing?

In the Typhoon.

Cosmo/Star: Mother...

Tails was looking at the readings of the seed.

Tails: This doesn't look good! Its energy is increasing so rapidly... our scanners can't measure it!

Eggman: Blast! The forestation process is getting too powerful for us to stop!

Back out in space.

Shadow leaped towards the seed.

Chris: Shadow!

Sonic: Let's help him.

Chris and Y/n nodded and they flew towards the pulsating seed.

Amy: You better hurry!

Chris: Ring Tunnel!

Chris fired out a Ring Tunnel.

Chris: Go, Sonic!

Went through the rings and hit the seed, but it didn't do anything and Sonic was sent back by some kind of purple-black gas. Shadow and Y/n fired a wave of Chaos Spears and and lightning respectively, but not even that did anything and the two hedgehogs along with the Tornado were sent back by the gas, back onto the Typhoon. Helen and Star instantly rushed to Chris and Y/n's side.

Helen: Chris, are you okay?

Chris: Yeah.

Y/n: Star...

Star: We need to regroup.

Helen: Well, I have good news and bad news. The good news is, the blast released the Chaos Emeralds from Dark Oak and me along with the Chaotix were able to get them back.

Y/n: I'm a little afraid to ask, but what's the bad news?

Helen pulled out a Chaos Emerald, but it wasn't glowing.

Star: Oh, no.

Helen: And it's not just this one.

Inside the bridge.

Team Chaotix was showing everyone the other Chaos Emeralds.

Vector: We got all the Emeralds.

Knuckles: But look; they're useless now.

Cream: Those poor Chaos Emeralds... All their power is gone.

Cheese: Chao chao...

Knuckles: That's just great! We don't have a single working Emerald! How can we fight back without extra power?

Eggman showed up on the big screen.

Tails: Eggman!

Eggman: Listen. According to my calculations, there's a chance we could restore the power of the Chaos Emeralds. However, it will take the energy of both out ships.

There was suddenly a bright light.

Bokkun: Doctor, something's happening!

Eggman: Huh?

The seed began to send out a wave that made everyone glow and feel weaker. The only ones who weren't affected by it were Cosmo, Star and Y/n.

Chris: I'm starting to feel weak...

Cosmo: What's happening, Tails?

Tails: Dark Oak is taking the life energy out of our bodies, just like they did to all the planets they attacked.

Eggman: It's drawing in all life energy it can find to spread plant life across the galaxy. It's the last stage of the forestation process.

Tails realized that Cosmo wasn't affected.

Tails: Cosmo?

Cosmo picked up the dead Chaos Emeralds.

Cosmo: Dark Oak cannot take my life energy away from me, because we both come from the same species of plant. I'll take care of this.

Star: Looks like it's up to me and Cosmo.

Y/n: I'm coming with you both.

Shadow noticed Y/n also wasn't affected.

Shadow: So how is the Faker not affected when me, the Ultimate Lifeform, is?

Y/n: My guess is that because I merged with Chaos, the wave doesn't recognize me as animal life.

Helen weakly tried to give her Emerald to Y/n.

Helen: Here... take the Chaos Emerald and...

She was about to fall, but Y/n caught her and laid her down before taking the Emerald.

Y/n: Don't worry, Helen. We've got this.

Y/n and Star nodded at each other before running to Cosmo who was climbing up to Eggman's ship.

Cosmo: The Metarex want to wipe out all animal life in the galaxy, but I still believe it's possible for plant and animal species to coexist in peace.

Cosmo: Just like I made friends with Tails and the others. And like how Star married Y/n. Dark Oak, there's still time for me to to stop your plan!

Cosmo began to hear Dark Oak's voice in her head.

Dark Oak: You cannot win... It's hopeless. What can one girl do to stop the Metarex?

Cosmo: Nothing you can say will make me give up! I have hope! Hope for a better future - a future of true peace! That's the kind of future my friends and I are fighting for!

The seed released a different wave that made a vine on the Egg Crimson grab Cosmo and smacked her against the ship

Tails: Cosmo!

Star: Sister!

While she was stunned, Cosmo drop the Emeralds.

Cosmo: I lost the Chaos Emeralds.

Star used her vines to grab three Emeralds while Y/n jumped in to grab the other three.

Y/n: And we got them again. Now let me see what I can do about this.

Y/n took all of the Emeralds and after a bit, they all began to glow again.

Star: Looks like they're back in action. Nice work, babe.

Y/n: Thanks. Why don't you two take five, me, Chaos, Sonic and Shadow will take care of the rest.

Cosmo: Are you sure?

Y/n: Trust me.

Y/n ran back to Sonic and Shadow and began to think.

Y/n: (Thinking: Should I really do this?)

???: Don't tell me you're scared.

Y/n: Huh?

Chaos appeared before him.

Chaos: Honestly, I don't think you've been afraid sense I've known you, my Lord.

Y/n: (Thinking: Would me going Super even be safe? What if something goes wrong and everyone gets hurt?)

Chaos: You've already come this far, are you going to stop now? Are you backing down?

Y/n's face became one of determination.

Y/n: Thunderhogs never back down!

Sonic: You both ready?

Shadow: All set. Let's finish this.

Y/n: Couldn't agree more.

All three of them began to absorb the Emeralds' powers and that made Sonic and Shadow enter their Super Forms. Meanwhile, Y/n also went Super, but his Chaos Form also began to change. The hands came off of the cape and three each formed a weapon. In Y/n's right hand was a shield. And in his left, a sword. Y/n's eyes went back to normal and his Chaos helmet took the shape of Perfect Chaos' head. Cream found Cosmo and Star watching everything from a distance.

Cream: What's going on?

Cosmo: Shadow, Y/n and Sonic are teaming up to stop the Metarex.

Star: And they're gonna take to those Meta-jerks.

Y/n used his sword to cut a spot into the giant seed and and the three went through it.

Chris: They'll be okay. I hope

The Hedgehogs kept going in and out of the seed and attacking it from everywhere until it exploded, leaving clouds everywhere. Everyone began to celebrate except for Eggman who felt something was off.

Dr. Eggman: Something is wrong. The energy levels are starting to reverse! Hm... It seems like it's imploding now.

The clouds moved away, revealing that there was now a pitch black planet where the seed was.

Dark Oak: Foolish hedgehogs! With the help of the Chaos creature, you have indeed prevented me from transforming the galaxy, but you can never win this battle. If the Metarex can't rule the galaxy, then we will destroy it!

Dark Oak let out an evil laugh as the planet began to radiate some kind of energy.

Tails: The pressure inside that thing is growing fast!

Vector: What's Dark Oak tryin' to do?

Chris: I know. He's producting a huge gravitational force, because he's trying to crush the Planet Egg.

Knuckles: But why is he doing that?

Chris: Imagine it's like a big balloon, and you keep on squeezing it tighter and tighter. You know what happens sooner or later, don't you?

Charmy: It goes bang!

Espio: Hold on. Are you telling us that thing's going to explode?

Chris: I'm afraid so.

Rouge: That sounds bad.

Helen: Tell me about it! The whole galaxy is gonna be destroyed because the, "mighty Metarex", are sore losers!

Cosmo: Dark Oak really is trying to destroy the galaxy.

Star: That cowardly bastard.

Sonic and Shadow tried to Spindash through the gravity field, but they couldn't even dent it. Y/n even tried to ram it with his shield and cut it with his sword, but he still couldn't get past it.

Y/n: We can't get through. Focus your power into containing it!

And that's exactly what they did. While they were containing the gravity field, the others were thinking of what to do.

Bokkun: Isn't there anything we can to to help break through that gravity field?

Dr. Eggman: Well... I've got one plan that involves you robots, but you won't like it. When you were built, I put special self-destruct circuits inside your bodies in case of an emergency such as this. I could set you off to break through the gravity field.

Decoe: But Dr. Eggman, that would destroy us too!

Bocoe: And besides, that gravity field is really powerful, so it would take a huge amount of energy to break through!

Decoe: Good point!

Chris: Eggman... please don't carry out that plan.

Dr. Eggman: Don't worry; I won't. The explosion wouldn't be strong enough to penetrate through the field.

Knuckles: Don't you have another plan up your sleeve? We're running out of time here!

Rouge: You claim to be a scientific genius. This would be the perfect time to prove it to all of us.

Back with the super Hedgehogs.

Shadow and Y/n were about to take off their limiters.

Sonic: Don't use that ring yet! In a few seconds, we're gonna need all the power we can get.

Shadow and Y/n listened and Sonic called to the others.

Sonic: Listen up, everybody! Our only hope of saving the galaxy is to throw all the energy we've got into this gravity field in one shot. Use the Lightning Sonic Power Cannon and launch me and Y/n at it!

Tails: It's way too risky! We've never launched you from the Power Cannon before when you were in your Super Forms. We don't have any idea what'll happen to ya!

Chris: That gravity field's extremely powerful, Sonic. If you two smash into it, the force could be too much for your bodies to take!

Knuckles: You mean to tell us there's a good chance Sonic and Y/n won't even survive the attack?

Amy: He can't do it! We have to come up with another plan!

Y/n: I have one. It's a really powerful attack that this form allows me to use, but the drawback is it'll burn through mine and Chaos' energy even faster.

Cream: But that's just as risky!

Sonic: I don't know if I can save the galaxy, but I have to try! And there's no way anybody's gonna talk me out of it, so save your breath.

Y/n: I may not want to die, but a Thunderhog never backs down!

Sonic: Now, are you gonna help us or not?

It was silent for a moment until Chris spoke.

Chris: Let's do it.

Sonic: Great!

Chris began working on a computer.

Chris: I'm routing all the energy in the network to the Power Cannon.

Tails: We only have one chance to break through that field. We'll need all the energy we can get.

Bocoe: Prepare to tranfer all power to the Blue Typhoon.

Decoe: Cutting off the ship's energy supply now and sending it to the Sonic Power Cannon.

The lights in both ships went off.

Bokkun: Be honest, Doctor. I wanna know what you think. Do Sonic and Y/n have a chance at saving the galaxy?

Eggman didn't say anything.

Back with Cream, Star and Cosmo.

Cream: I'm so nervous I can't even look.

Cosmo: I feel helpless...

Star: There's not much we can do, except pray that it works.

Cosmo's amulet began to glow white as she heard the voice of her mother again.

Earthia: Cosmo. This is the moment we've been waiting for. You can help save the galaxy and our clan if you only believe in yourself.

Cosmo: This is why I was sent here...

Star: Sister?

Cream: Are you okay?

Cosmo: I understand now. There can be peace in the galaxy, and I have the power to make it happen.

Cream: What do you mean?

Cosmo began to levitate.

Cream: Where are you going?

Cosmo's amulet broke and she began to take a Bloom Form like Star as she grew bigger, her rose buds bloomed and she began flying towards the planet.

Star: (wide eyed) Cosmo, no!

Cream: What's going on?

Star: There's something about Seedrians I forgot to mention. If we Seedrians desire, we can turn into trees to enter a state recovery or at times, reproduction! And she's about to plant herself on the planet to surpress the gravity field.

Cream: What?!

Star: Cosmo, please don't do this! If a sacrifice must be made, let it be me instead!

Star was about to re-enter Bloom form when Cosmo stopped her.

Cosmo: Star, you've always known what to do, found a way to be useful while the only thing I could do was watch from a distance. So please, let me take this chance to finally be useful for once.

Tears began to leave Star's eyes.

Star: Cosmo...

Cosmo: When you and Y/n have children of your own, tell them that their Auntie Cosmo loves them a lot.

Cosmo flew towards the planet while Cream hugged up to Star.

With the Hedgehogs.

They were still holding back the gravity when they noticed Cosmo.

Y/n: Cosmo?

Sonic: Why are you here?

Cosmo: (Thinking: Mother, I feel really happy now because I finally know what my purpose is!

Cosmo easily got past the energy field.

Cosmo: (Thinking: My friends and my sister mean more to me than anything. That's why I give up everything to save them.)

A bright flash of light occurred as soon as Cosmo hit the planet's surface. When it dissipated, a gaint, cherry blossom tree was on top of the planet. Everyone was left speechless, when they heard Cosmo's voice.

Cosmo: It's all right. I have Dark Oak immobilized. Now you'll be able to destroy the Metarex and save the galaxy. Don't worry about me. Just fire the Power Cannon now.

Chris: But if we fire the cannon, what'll happen to you?

Tails: If she says not to worry, I have to trust her.

Tails was setting up the controls of the cannon, but he didn't seem too happy about it.

Eggman: (Over radio: Tails, we must act immediately! Prepare to fire the cannon at my command!)

Y/n: No, there has to be another way. Cosmo is my-

???: My Lord!

Y/n heard Chaos again and before Y/n was a transparent image of Perfect Chaos.

Chaos: This could be our only shot! I may have had my disdain for your sister-in-law, but she's giving us an opportunity we can't throw away.

Y/n thought for a moment before he and Sonic took off towards the Typhoon where the cannon was getting set up.

Eggman: Plug cannon into place and take aim.

Sonic flew into the Power Cannon while Y/n stayed on the outside.

Eggman: What are you doing, Y/n?

Y/n: I'm doing this with my own power, not with a machine.

Eggman: Hmm. Get ready, you two.

Shadow flew into the cannon with Sonic who smiled and nodded at Shadow before the cannon began to charge them up with energy. Meanwhile, Y/n summoned the transparent image of Perfect Chaos and began to spin around in it.

Bocoe: Sonic and Shadow are attacking together!

Decoe: Which means this blast will be twice as powerful!

Bokkun: And that's not even counting whatever Y/n's cooking up.

After a minute, the Cannon was ready to fire.

Eggman: Sonic Power Cannon, fire!

Tails: Roger!

Tails with tears in his eyes, hesitated to pull the trigger.

Tails: Ah! I can't! I just can't do it!

Eggman: (Over radio: Tails, I know this is difficult, but the galaxy is in danger, and time is running out! You must fire now!)

Tails began to break down.

Tails: I-I can't... What about Cosmo...?

Eggman: (Over radio: She knows what she's doing. Cosmo is carrying out her destiny. She was meant to save the galaxy, and we have to help her.)

Tails looked at the tree that was Cosmo.

Tails: I'm sorry, but I just can't do it.

Tails began to hear Cosmo's voice.

Cosmo: Tails, I'm sorry that I keep troubling you, even now.

Tails: Cosmo... You never caused me any trouble!

Cosmo: I want you to shoot me, Tails.

Tails was shocked, and harshly closed his eyes.

Tails: I can't!

Tails put away the trigger.

Tails: Because... Cosmo, I...

Tails began to remember all the good times he had with Cosmo. From finding her, to the falling in the lake on Planet Marmolone, to cheering her up. Then Tails heard Star's shaky voice.

Star: Do it, Tails.

Tails: What? But...

Tails saw tears waterfalling down Star's face.

Star: You think this is easy for me?! Cosmo is the only family I have left! I wish there was another way, but if she wants this, then I have to respect it! So, please, just get it over with.

Tails still wasn't sure, but he reluctantly pulled the trigger, firing Sonic and Shadow so hard that it destroyed the cannon. Meanwhile, Y/n's attack was finished charging.

Y/n: If this is what you want Cosmo, then here it is! Final... Chaos... SLASH!!!

Y/n was launched from the mouth of Perfect Chaos and as Sonic and Shadow went straight through the planet, Y/n finished the job by cutting it in half, causing a big explosion.

Y/n: Cosmo... Star... I'm sorry.

Y/n let a single tear fall.

To Be Continued.