3rd POV:

Sonic and his friends have successfully barged through the gauntlet of doom in Eggmanland. They venture across, went into the temple, and restored the final Chaos Emerald while the continent was in place. However, Dr. Eggman arrived along with his latest invention; the Egg Dragoon, attacking them. At the end of the battle, they successfully destroyed the Egg Dragoon as Dr. Eggman has been defeated, his empire and his plans for world domination came to an end until…

Eggman: How could I lose?! This isn't over! I'll build a Prototype-2 and it… hmm?

As the lava rises, the dark flame tentacles of a gargantuan creature of darkness slowly rise from the lava. Sonic, Chip, Y/n, and his summons are shocked to witness what's happening.

Sonic: What the?!

Chip: Whoa!

Y/n: Talk about humongous!

As the dark gargantuan creature kept rising from the lava, Chip realized what it was.

Sonic: What!

Y/n: Chip, is that what we think it is?

Chip: Yes, it's Dark Gaia!

They were still shocked to see… Dark Gaia is finally awakened and complete. It has brown skin with its lower body and torso resembling that of a snake's, two thin arms with long neon-blue claws, and scaly shoulders. Its head is very wide, much wider than its main body, and is mostly composed of its jagged mouth. Its central face looks like that of a reptile's, with four small horns on the top of it and white eyes

Y/n: We made it this far, there's no way we're back down from this!

Sonic: Yeah! We'll find a way to defeat that thing before it's too late!

Everyone agrees with Sonic and Y/n.

Eggman: Yes, YES! Dark Gaia! Crush this insolent little hedgehog!! Kick him to the outer limits of space!! Hmm?!

Dark Gaia's dark flame tentacles hit the cockpit as Eggman flies off to nowhere.

Eggman: Why meeeeeee?!

The dark flame tentacles from Dark Gaia are attacking Sonic and his friends. They noticed it was heading towards them.

Sonic: Everyone, move!

Sonic grabs Chip, Pikachu on Latios, and Riolu on Latias, and Y/n have dodged the dark flame tentacles and gets onto another rocky platform. They landed safely and looked at Dark Gaia. However, Dark Gaia's eyes shine bright, making direct contact with Sonic. As they are ready to fight, they notice something is wrong with Sonic, as he kneeled to the ground in pain. They grew concerned for Sonic.

Chip: Sonic! What's wrong!?

Y/n: Hey, are you okay?! Please talk to me, Sonic!!

Y/n’s Summons: Pika!/Riolu!/Latios!/Latias!

They see what's happening to Sonic, his teeth, and his claws are shrinking and his spikes are coming off. Sonic is shaking up violently as what happens next.

Sonic: Aaaggghhh!!!

Sonic yelled out in pain as the dark energy was coming out of him completely towards Dark Gaia. Dark Gaia has absorbed all of Sonic's dark energy, Dark Gaia's forehead opens up three eyes and roars. Chip and Y/n’s Summons are a bit afraid of what they've witnessed, Y/n is shocked but he stands his ground as he won't back down. They snapped out of it and checked on Sonic, he was no longer in his Werehog form anymore.

Chip: Sonic, you've got to get up! Sonic!!

Y/n: C'mon Sonic, hang in there buddy! We'll find a way!

Pikachu: Pika, Pi!! Pikachu!!

Riolu: Rio! Rio!

Latios: Tios! Latios!

Latias: Tias! Latias!

Sonic: Everyone. R-run, guys!

They were shocked to hear Sonic, telling them to run. Y/n’s Summons is on the verge of tears

Pikachu: Pika! Pika! Pikachu!

Riolu: Riolu! Rio!

Latios: Tios! Tios!

Latias: Tias! Tias!

Y/n widens his eyes as he remembered recently. The mind flashes to his recent battle in the alternate world of Earthland where Dante Dreyar Vermillion lived there. He remembered Dante smiling as he was ready to save his family and friends, even mentioning that it will cost his entire life. Y/n snapped out of his mind, looked at Dark Gaia in determination, and moved in front of Sonic and Chip.

Sonic: Y-Y/n, what are you… doing?!

Y/n: No. Not this time. If we let that monster live, it will destroy everything. I'm not letting my friends die, not on my watch.

Y/n was equipped with his Rebellion’s Oath Keyblade and made his battle stance. Sonic and Chip are surprised to see Y/n never give up, they see the fire in Y/n’s eyes and Y/n’s face of determination to protect what matters to him. Chip looks at Y/n as if he was right, looking back at Dark Gaia. As the dark flame shots were coming towards him and Y/n was about to fight back, Chip flew past Sonic, Y/n, and his summons.

Y/n: Chip?! What are you?!

Chip: HAAAA!!!

Chip cast a green force field around them and protected his friends. They were speechless at Chip's bravery, until…

Chip: Seven lights… of the earth… Rekindled!

In each of the seven continents' Temple of Gaia, the seven Chaos Emeralds glow brightly and shoot straight up and the temple starts to shake and float up in the sky.

Boy: What's happening?!

Old man: That's just incredible!

Man: The temple!

The seven temples disappeared in front of their eyes, it's heading toward where Chip is calling and where Dark Gaia is.

Chip: Awaken, and gather here to me!!!

The seven temples are coming towards Chip, starting to merge along with the seven Chaos Emeralds as well, and now fully assembled as the Gaia Colossus.

As Y/n and his summons slowly opened their eyes and they looked around to see they were on the Gaia Colossus. From Y/n's Ki Sense ability, he senses Chip somewhere. Pikachu's ears twitched and Riolu's aura sensed a familiar presence and groaned.

Pikachu: Pika, Pi!

Riolu: Rio! Rio!

Y/n, Latios, and Latias looked where Pikachu and Riolu were pointing and saw Sonic starting to wake up from the dark energy extraction. They hurry to where Sonic is and relieved to see Sonic is okay.

Sonic: Wha? What happened?

Y/n: Here, eat this. It will make you feel better instantly.

Y/n handed Sonic a Vital Star L, Sonic looked at Y/n who smiled and nodded, Sonic nodded, ate the Vital Star and he recovered quickly.

Sonic: Thanks a lot, Y/n! But where are we and, where's Chip?!

Y/n: Not sure where Chip is, but he is here somewhere close by.

Chip: Sonic! Everyone!

Sonic and his friends look behind them and they are surprised to see Chip is in the Gaia Colossus, and they're on him.

Sonic: Chip, is that you?! Wow!

Y/n: *smile* You are an awesome friend, Chip, ya know!?

Y/n’s Summons: *smile* Pika!/Rio!/Tios!/Tias!

Chip: *smiles* Thank you, my friends! Now… It's my turn!

(Vs. Dark Gaia theme)

Dark Gaia roars and it's ready to destroy the Gaia Colossus. The Gaia Colossus or Chip is ready to fight against Dark Gaia for the sake of the planet and all living things for the final battle.

Sonic and Y/n: Here we… GO!!!

The Gaia Colossus is starting to boost through the air as Dark Gaia throws lava rocks toward Chip. The Colossus has managed to keep going as he throws a few punches and dodges them. As the Colossus continued to boost in the air, Dark Gaia was charging up a beam attack.

Sonic: Oh no, it's starting to shoot at us!

Y/n has an idea in mind, he formed his demonic wings, flew in front of them, and started to cup both of his hands as ki energy formed fast.

Sonic: Hey Y/n, what are you–?!

Y/n: Kamehame… HAAAAAAAAA!!!

Y/n did the Kamehameha technique as Dark Gaia shot its beam toward them and it collided. Y/n was able to hold on, he roared with his might, his technique winning over and Dark Gaia was stunned for a moment. Y/n went back to Sonic and his summons.

Sonic: *smirk* That was crazy, but it did the trick! Awesome job, Y/n!

Y/n: *smirk* Thanks! I had some help! Keep going, Chip!

Chip: Right!

The Gaia Colossus continued to boost through the air until he made it close to Dark Gaia. As Dark Gaia was about to shoot a beam attack again, Chip throws punches in the face. Dark Gaia attacks Chip with a claw strike but Chip dodges and retaliates by throwing strong hooks and jabs.

(Vs. Dark Gaia Running theme)

Dark Gaia slowly grows agitated, it starts to grab hold tightly of Gaia Colossus as it's charging for a strong attack. Chip is holding Dark Gaia back.

Chip: Everyone! Now, my friends!

Sonic: Roger that, buddy!

Y/n: We'll split up left and right, and finish off the middle eye together!

Pikachu and Latias went up to Y/n while Riolu and Latios went up to Sonic.

Riolu: Rio!

Latios: Tios!

Sonic: Right! Let's give everything we've got!

Pikachu: Pika!

Latias! Tias! Tias!

Y/n: Okay! After you guys finish, Sonic and I will take it from here! We got this!

Y/n’s Summons agreed with Y/n's response and went separate ways as Y/n’s team went to the left side and Sonic's team went to the right side.

Sonic and Y/n: Time for the big finale!!!

On Y/n’s side, Y/n runs through the road as he dodges the dark tentacles and incoming shots. Y/n uses his Flowmotion abilities to maneuver the building to wall kick, rail sliding, and leap to another platform. As they made it where the left eye was, Y/n was equipped with his dual pistols Ebony and Ivory and called out his friends.

Y/n: Pikachu, use Thunderbolt! Latias, use Dragon Pulse! Let's go!

Pikachu uses Thunderbolt, Latias uses Dragon Pulse and Y/n charges his ki energy and dual shot at Dark Gaia's left eye. Y/n, Pikachu, and Latias landed back on the Gaia Colossus, Pikachu and Latias cheered Y/n for good luck and went back inside of Y/n.

On Sonic's side, Sonic runs through the road as he dodges the dark tentacles and incoming shots. Sonic maneuvers as he wall jump, rail slides, and jump onto another platform. As they made it, Sonic readied his move.

Sonic: You guys ready?!

Riolu: Rio!

Latios: Tios!

Sonic: It's now or never!

Sonic unleashed a barrage of his homing attack, Riolu used Close Combat and Latios used Luster Purge at Dark Gaia's right eye. Sonic, Riolu, and Latios landed back on the Gaia Colossus. Riolu and Latios cheered Sonic for good luck, Sonic gave them a thumbs up and they went back inside of Y/n.

Chip: Sonic! Y/n! Hit Dark Gaia's last weak spot, quick, while I hold him back!

Sonic and Y/n: Chip, you rock!!

Sonic and Y/n met up and started to run through the road and maneuver the obstacles ahead.

Chip: Hurry, guys! Dark Gaia's getting ready to do something!

Sonic: Hang tight, Chip!

Sonic and Y/n managed to avoid more dark tentacles and incoming shots as they kept going and saw they were getting close.

Chip: Hurry, guys!

Y/n: We're almost there!

Sonic and Y/n have finally made it to the middle eye of Dark Gaia, Y/n does a flurry of punches and kicks while Sonic does a bunch of homing attacks. Sonic and Y/n jumped up in the air and prepared for the final blow.

Sonic and Y/n: *smirk* Let’s go/Jackpot! Rraagh!!!

Sonic does his final homing attack and Y/n spins himself with a strong ax kick. Sonic and Y/n have successfully destroyed the three eyes of Dark Gaia, go back and Gaia Colossus catches them.

Sonic: Whew! Alright!

Chip: Incredible, you guys!

Y/n: Is it over?

They looked at Dark Gaia but they were shocked to see that Dark Gaia rises again.

Y/n: Now what?

Sonic: What the?!

Dark Gaia raises its head and shoots out its darkness all over the planet. Throughout the planet, the people are now in a fearful state as the planet is doomed.

In the village of Shamar, Amy ran outside along with Professor Pickle to catch up and see what was happening to the sky.

Amy: Wh-what's happening? It was broad daylight a minute ago!

Pickle: Dark Gaia has regained its true power. The beast is complete. It's just as the Gaia Manuscripts foretold. "And the world shall be plunged into the dark of night, the dark of destruction" Oh, that it should come to this! We're doomed. The planet is lost!

Amy: That won't happen! There's no way Sonic will let it end like this!

Back at the center of the planet…

Sonic, Y/n, and Chip are shocked to see Dark Gaia roar but they're seeing what happens next. They see Dark Gaia burst out four extra arms on its torso, its gigantic mouth opens wide revealing six eyes, and a huge eye in the middle. Dark Gaia is now in the Perfect Form state. The planet piece pushed up as the darkness spread.

Y/n: We'll stop that monster, we have to. We're not letting Dark Gaia destroy the planet! We'll never give up!

Sonic looked at Y/n, to see he still had the same fire. A strong heart and a strong will, still determined to save what matters to them. Sonic smiled and he had an idea… for them.

Sonic: *smirk* Now that's the spirit! It's time!

Y/n: Wait, for what?

Sonic: *smirk* For the seven Chaos Emeralds, we're going to use it and be super together!

Y/n: What?! I can?!

Sonic: Remember what I told you back in Apotos? Once all seven emeralds are gathered, a miracle will happen filled with positive thoughts, hope, and connections with our friends and family.

Y/n was surprised a bit that what Sonic said was true, he let him continue.

Sonic: We made it this far because of our hearts, soul, and the bonds of friendship. I can tell from looking at you, it clearly shows. Now, let's finish this together!

Sonic raises his fist in front, Y/n knows what that means, smiled, and gave Sonic a fist bump. While their fist bumped, Y/n's Wayfinder is glowing brighter, time stops and they see the white void. And they began to hear some voices.

Tails: You can win, you guys!
Amy: Please be careful, Sonic!
Pickle: We're counting on you, Sonic, and Y/n!
Chip: Let’s finish Dark Gaia together, my friends!
The rest of Sonic's friends cheered.

Pikachu: Pika, Pi! Pikachu!
Riolu: Rio! Riolu!
Latios: Latios!
Latias: Latias!

While kept going, Sonic hears more voices that are unfamiliar to him but Y/n, knows them well and smiles.

Sparda: Go forth, my grandson!
Eva: You can do it, sweetie!
Dante: I know you're stronger than that, kiddo!
Trish: We're with you, my little hunter!
Lady: I know you got this, Y/n!
Nero: Give everything you got, Y/n!
Kyrie: We believe in you, Y/n.
Emiko: You can win, Y/n!
Vergil: Show them your power and motivation.
???: Henceforth, Son of Dante.
???: That's right, superstar! You got this!
A panther roars with encouragement.
Dante(SoM): You got the power, rival!!

Kuroka: I know you can do it, darling!
Asia: Please come home to us, Y/n!
Rossweisse: Don't give up, Y/n!
Chisato: You're not alone, Y/n.
Sona: Please live for us, Y/n!
Serafall: Go for it, Y/n-kun!
Sona's Peerage: Win Y/n, Win!/We're with you!/Focus on your spirit!/You got this!
Latina: Be careful, papa!
Grace: We're waiting for you, daddy!

Natsu: Get fired up, Y/n! Blast it sky-high!
Happy: Aye sir!
Lucy: You can win, Y/n!
Wendy: Don't give up, Y/n!
Carla: Be strong!
Ur: I believe in you, honey!
Gray: Come on, Y/n! We're still friends!
Juvia: Juvia trusts a friend of Gray!
Erza: I still love you, Y/n! We can't lose you!
Irene: We're waiting for you to come back home, Y/n!
Heine and Juliet: Rise up, Y/n!
Cana: Show them what you made of, in Fairy Tail style, Y/n!
Mirajane: Fairy Tail is always with you, Y/n! I'm with you!
Elfman: Show them that you're a real man, Y/n!
Lisanna: We all cared about you, Y/n! I do too!
Gajeel: You better not lose, Y/n!
Panther Lily: We'll be with you in spirit, Y/n!
Levy: Giving up is never in our dictionary of Fairy Tail, Y/n!
Laxus: Crush those enemies, show them the spirit of Fairy Tail!
Freed: The Thunder Legion is at your side, Y/n!
Bickslow: We'll never back down that easy, we're the strongest together!
Evergreen: We fairies never give up on what we believed in!
Makarov: Y/n, we’ll rise up and show them! We don’t know the meaning of giving up!
The rest of the Fairy Tail members cheered.
Mavis: The unwavering faith and resilient bonds will bring even miracles to your side, Y/n.

Everyone: *smile* Y/n!!!

Y/n opened his eyes, looked at Sonic, smiled, and nodded. Sonic noticed Y/n’s determination of his expression as he was ready and he nodded in return. The Chaos Emeralds begin to glow brightly within the temples as it flies up to where Sonic and Y/n are. The Chaos Emeralds go around Sonic and Y/n, and they're ready for what's about to happen.

Sonic and Y/n: Let’s do it!

As the seven Chaos Emeralds spin around them and glow brightly, Sonic and Y/n close their eyes in concentration, and they have transformed. Sonic's fur glows into golden yellow, the quills pointed up, and his eyes are red. As for Y/n, his hair glows golden yellow as well, his hair grows a bit and is pointed up, and his eyes are shining sky blue.
(Imagine Y/n is like Super Saiyan Goku)

(Vs. Perfect Dark Gaia- Endless Possibilities)

Perfect Dark Gaia roars as it's ready to destroy everything on the planet and forms a barrier with those dark tentacles. At instinct, the Rebellion’s Oath Keyblade appeared in Y/n’s hands, and knew what to do.

Sonic: Alright guys, time for the big finish!

Y/n: Yeah, we can do this!

Chip: Sonic!

Chip, Sonic, and Y/n started to boost through the air as they dodged rocks floating around. They see a few dark fires shot from Dark Gaia, Y/n has an idea and goes in front of Sonic. Y/n concentrated the energy from the Chaos Emeralds, synchronizing with his keyblade, aiming where the dark projectiles and the energy formed at the tip of Y/n's keyblade.

Y/n: Chaos Ragnarok!!!

Y/n fires a cluster of energy shots back at the dark projectiles and it explodes. Y/n is amazed that his attacks are stronger than before.

Y/n: That's awesome! Is this because of the Chaos Emeralds?

Sonic: It sure is! Come on!

They continued to boost through the air until they saw the barrier was already formed.

Sonic: Rrgh! We've got to take out that shield!

Sonic and Y/n looked around until they saw Chip.

Chip: My turn, Sonic!

Y/n: What?!

Sonic: H-hey! What are you doing, Chip?!

The Gaia Colossus started to go through the barrier.

Chip: Rh… RrRAAAAGGHH!!

They were surprised Chip had made it through the barrier.

Y/n: Awesome, Chip!

Sonic: Chip, I… you were… Wow!

Chip: I'll get its attention! You guys do something about this shield!

The Gaia Colossus started to fight Dark Gaia, to distract it.

Chip: I think those big snake things are creating the shield, you guys!

Sonic and Y/n noticed there were dark tentacles around the barrier, they also noticed there were eyes in it like before.

Sonic: Looks like those snake things are its weak spot!

Y/n: Right, let's go!

Sonic and Y/n started to boost around and take down those dark tentacles that formed its barrier while they dodged floating rocks. Sonic charges in three tentacles and moves on to the next.

Chip: I-I can… I can still… fight.

They noticed that Chip is stunned by Dark Gaia's attacks. Dark Gaia has spotted Sonic and Y/n, and uses telekinesis to lift magma rocks and throw them toward them as meteors.

Y/n: I got this one! Chaos Strike Raid!

Y/n concentrating, synchronizing with his keyblade and throwing around the magma rocks. However, Dark Gaia isn't done as it's charging up for a blast attack. Y/n cupped both of his hands, concentrating by combining his ki and Chaos Emeralds' power, and formed a combined energy ball.

Y/n: Chaos Kamehameha!!!

Y/n launches the Kamehameha wave with the power of the Chaos Emeralds and clashes with the Dark Gaia's blast. Y/n looked at Sonic as he was helping him, smiled, and nodded at Y/n, and Y/n nodded as acknowledged.

Sonic and Y/n: Together! HAAAA!!!

Sonic and Y/n pushed through Y/n's Kamehameha, which they managed to overcome the Dark Gaia's blast and stunned for a moment. Chip woke up and noticed that Sonic and Y/n managed to stun it.

Chip: Amazing, my friends!

Sonic: Thanks to Y/n! We'll take care of those snake things!

Sonic and Y/n kept going to boost through the dark snake-like tentacles, they took down all of the tentacles as the shield disappeared.

Sonic: Yes! The shield's gone!

Y/n: Alright!

Chip: My friends! You did it!

However, Dark Gaia strongly gripped the Gaia Colossus, unable to break free. And Dark Gaia charges up its blast attack.

Chip: Nnguaaagh!! Nnrrrgh!!

Sonic and Y/n: CHIP!!!

Sonic: Be right there!!

Y/n: We're coming!!

Sonic and Y/n rushed in to help Chip, Sonic went to the right side to blast through its arms while Y/n blasted through with his keyblade on the left side and they were up to the last one.

Sonic and Y/n: Eat THIS!!

Sonic and Y/n blast through the last arms and Chip is free from its clutches but Dark Gaia releases its beam toward Chip. The Gaia Colossus blocks Dark Gaia's beam, he successfully deflected its beam, rushed towards Dark Gaia, and threw a strong punch.

Chip: Now, my friends!!

Y/n: *smirk* Sonic, grab hold of my keyblade, and let's finish this together!

Sonic: *smirk* Ready whenever you are, pal!

Sonic and Y/n looked at each other and nodded as they were ready for their final attack. They both charge up.

Sonic and Y/n: Here's Sonic!/Y/n! Chaos Stinger Boost!!!

Sonic and Y/n charge toward Dark Gaia while Y/n points out his Rebellion’s Oath in front, Sonic grabs Y/n's keyblade and rushes to Dark Gaia for the final blow.

Sonic and Y/n: HAAAAA!!!

(Final Boss theme ended)

Sonic and Y/n have pierced through Dark Gaia's middle eye and both fly up. They began to see Dark Gaia turning into goop as it fell into the lava. Dark Gaia is finally defeated.

Chip looked at Sonic and Y/n, he was grateful for their bonds of friendship and bravery to restore the planet. Y/n looked at his hands, seeing them glow, smiled, and placed where his heart was.

Y/n: 'Everyone… thank you.'

Y/n noticed that Sonic looked at Y/n, he was exhausted and smiled and tried to give them a thumbs up but his form was worn out as he fell in exhaustion.

Y/n: Sonic!

As Y/n tried to reach out to Sonic but his super form wore off and started to fall. Y/n continues to fall the lava as he grabs Sonic but his fatigue is slowly taking over. The Gaia Colossus managed to cast a green force field around them and landed safely on his hand. Sonic and Y/n are unconscious.

As the last piece of the planet is moving back into place, the townspeople of every continent are very happy and relieved that their world is saved from the destruction of Dark Gaia.

Somewhere on the land, Eggman came out of his damaged vehicle and he was depressed that his plans had failed. Orbot came out of the vehicle.

Orbot: Pleasant morning. Wouldn't you say, Doctor?

Eggman was still depressed about how he didn't take over the world.

Orbot: You can simply begin your plans anew. Even if all of your efforts this last time were utterly wasted. Even if it was a complete and utter humiliating loss. Even the most pathetic loser in all the world will surely have his chance to-

Eggman: Oh, shut up!

Eggman tries to kick the robot, but misses and he falls to the ground.

Orbot: Ha ha ha ha!

Eggman: Ahhhhueeegraashhh!

Eggman chases after the robot over the sunset.

What happens to Sonic and Y/n?

Stay tuned for the final chapter!