Sonic Frontiers and MLP: The Beginning and Ending Of The End

Knuckles wants a vacation / Wyvern Fight

Sonic Collects the 6th Chaos Emerald while this happens during "Frenemies" with the Legion of  Doom retrieving Grogar's bell

(Knuckles is seen with the army of soldier Kocos, who is sobbing in fear)
Knuckles: [To the Kocos] I don't care if you're afraid! Those are your people out there!
Sonic: Hey, coach, what's with the pep talk?
[Knuckles grunts in anger.]
Knuckles: With the defenses down the soldiers are supposed to fall back to a bunker.
Sonic: Then I'll round-up the stragglers and you supervise, commander.
Knuckles: That sounds... that sounds good.

[Knuckles sees the bunker and has a flashback scene of Angel Island from Sonic 3 (& Knuckles).]

Sonic: Is this the place? [Knuckles doesn't listen] Yo, Knux?
Knuckles: Sonic, this... this looks like ruins from back home. What if the people of these islands survived and resettled on Angel Island? That'd make this pretty important.
[While the group of Soldier Kocos march, one of them sees something. With another Koco colliding into it from behind it sees something and starts yelping, alerting Sonic and Knuckles.]
Sonic: That's not a good sound.
[All the Kocos retreat. Sonic and Knuckles look up. Several 'Towers' appear.]
Knuckles: They're going to assault the bunker! [Has the flashback in his head] I can't... I can't lose this!
Sonic: We've got this buddy. I've got your back!
Knuckles: Thank you, Sonic.

After destroying all the towers Sonic Knuckles and all the Kocos gather up. They all saluted and the Kocos spirits went up to the sky leaving them dead to the ground with a depressed Knuckles.

Knuckles: Ages ago my people were wiped out by a cataclysm. I know the Koco faced something similar. It reminds me I'm the last Echidna. That I'm alone.
Sonic: You may be the last but you're not alone. You've got us, Knucklehead.
Knuckles: I'll admit. I do envy your lifestyle. Freedom to go where you want, when you want.

Sonic: So do it! Get out there and live a little.
Knuckles: Maybe I could... but first, I need to be back to normal. So hurry up, and get me back to normal!
Sonic: Anything to get you away from me!
[Sonic and Knuckles stare competitively at each other again. Shots of their pupils show on screen. Soon the seriousness turns into laughter and they share a fist bump. Sage is below the duo.]
Sage: He helps those he is at odds with. He is quick to make peace. Perhaps... [Thinks] No, I have run the simulations. They are doomed.

Later Sonic and Knuckles found a crane and big stone balls with different colors (red, yellow, blue and white)

Knuckles: Sonic! Check these out. I don't think this ancient Machinery was active before. Any idea what changed?
Sonic: Something similar happened on the last island. Let's just call it a little "divine intervention." If I can solve the locks code, it should open the way to that flying Titan.
Knuckles: Wait, Sonic. You're still missing a Chaos Emerald, aren't you? Well, that thing will tear you to shreds.
Sonic: The last Titan was holding the final Emerald. I'm willing to bet it's the same deal here. First, though, I need to play this crane game. Let me see... the stones and the ports seem to have corresponding colors.

After placing the stones to the right color a bigger boulder comes out of the cave.

Knuckles: Huh. You did it. Nice work.
Sonic: Was there ever any doubt? Ready to go face impossible odds?
Knuckles: Ha! We faced worse. Here we go! Try to keep up!
Sonic: Whoa, hey! That's my line!

As Sonic follows the path it leads straight into a opening with a tall tower and Wyvern is flying over. Sonic would soon climb the tower to reach the top .

As Sonic reaches the top he used Wyvern's red trail as a path to chase after it, eventually reaching its head and claiming the purple Chaos Emerald, allowing him to transform into Super Sonic. All powered-up Sonic and the Titan were engaged into battle flying all over Equestria and reaching the Mount Everhoof. Super Sonic grabs the Titan's tail and throws it towards it causing an Avalanche with Rusty Bucket still on the lower ground, Sonic saw him and goes to save him.

Rusty Bucket: Oh no Not again! (Arrives and saved him)
Rusty Bucket: Sonic The Hedgehog?
Super Sonic: Yeah That's me.
Rusty Bucket: I've heard so much about you.
Super Sonic: Yeah thanks. Hey uh sorry about the mess.
Rusty Bucket: No worries I do this a lot.
After saving him Sonic continues his battle with the Titan.

Ancient: They're... gone. It killed them.
[Super Sonic swoops down to Knuckles.]
Knuckles: Not bad! Things would have been over faster if I'd been "Super Knuckles", but you did all right.
Super Sonic: Yeah, you keep telling yourself that. I've got one more Titan bot to go. Hopefully I'll find Tails too. I'm worried about him.
Knuckles: He'll be all right. Now, hurry up and save the day already!
Super Sonic: Yeah will do how about you head back to Twilight's castle. Amy's is there waiting as well.
Knuckles: Got it. And what are you gonna do?
Super Sonic: Well I gotta help somepony for the moment. His house is fully covered with snow
Knuckles: Heheha good luck with that I'll see you later Sonic. (Knuckles disappears)

Super Sonic heads to Rusty Bucket's location

Rusty Bucket: Oh well guess I'm gonna have to clean this myself again.
Super Sonic: Maybe I can help you that Rusty Bucket.
(Uses Cyloop and removes all the snow from his house)
Rusty Bucket: Oh hoho! Why thank you so much Sonic! Hey can you help me for little bit inside please?
Super Sonic: Sure.