This is how the ending goes in Kingdom Hearts X (Chi) Back Cover.
Laval: So, why you called us, Ava?
Ava: You see, I called all of you and your friends about your training. The Master told me, that you grow alot stronger since all those Missions I gave you, and now you're Powers has been Awakened. This time I named you all Keyblade, Digimon and Warrior Master.
They are now cheering because they became a Master of Keyblade, Digimon and Warriors
Ava: Yes, that's good.... but I have something to tell you all, the Master told me that you were from the Future in 100 Years. So, he told me to make sure that you will grow stronger and awakened your new Power. And after that, I should send you back to your own timeline.
Natsu: We can go back to our homeworlds!
Ava: Actually, all of your world is gone to Darkness... but, there is a world where you can stay, help the people and training with them. After you go back in time, there is no returning to the world that you came from. Once, you got there. You will be safe from the Keyblade, Digimon and Warrior War.
Happy: Okay, thank you.
Then Erza realised something
Erza: Wait, I just realised something. You said "After you go back in time, there is no returning to the world that you came from. Then that means...
Ava: Yes... All of you, will never come back to Daybreak Town ever again.
Ava: I'm sorry, but it's the only way for you to be safe. I don't want you all to be in the War. Even though, you're from the Future 100 Years, so I can't let that happen to you. Laval, Shu, Happy. You have a Choice to make, you should go back in time and be safe to the World where you can be safe... or you should stay here and face the Keyblade, Digimon and Warrior War.
Laval: We got a choice?
Laval, Shu and Happy knows that they will never come back to Daybreak Town even again, they will everyone here in town, so now they made their choice
Laval, Happy & Shu: Take us to a world to be safe.
Ava: Well, Okay. Everyone will miss you here in town, but when you go to the world where you can trained, many people who can take care of you.
She take them to three Trains
Lucy: So. We have to go on these trains?
Ava: Yes, Vivi is going back his world with Lann and Raynn. And all of you will go back to your timeline.
Natsu: I have to ride on that train? No way, I get emotion sickness!
Ava: I know, you're a Dragon slayer, but it's the only way for you to be safe.
Razar: But, what do we after we left Daybreak Town?
Lucy: And how can we say goodbye to everyone, after we left?
Ava: Maybe I can write a message. It will say "Thank you, everyone."
Wendy: Really? That's good, it makes me feel better.
Worriz: Well, See ya, Ava.
Ava: Goodbye, everyone.
They went to three Train
Ava: You too. Laval, Shu, Happy and Vivi.
Ava: All of this may have started with the booklie... but I'm really am glad that I could meet you, Laval, Happy, Shu, Vivi.
Vivi: Yeah, when I was in the Realm of Darkness with Lann, Raynn, Modecai, Rigby and three Digimon's. I finally that you created me, not Kuja or the Mist Continent. You're the one who created me.
Ava: Really? You think I created you?
Vivi: Yeah, I'm so happy to return to Daybreak Town for a whole year. Now, it's time for me to go away now, Seifer and the Gang knows that I'm gone. Now, I have to go back to them.
Shu: Yeah, me too. When we came to this world, and even when we became Pupils, I was happy. The way I felt then- That was a Memory.
Laval: Hey, it's not a Goodbye, Ava.
Shu: When we left this train, we'll find you. And then, we can be friends. Promise us, Ava.
Happy: Promise us, Ava.
Ava: You're going to miss this town, making that promise.
Laval: If the timeline apart, the link will still be there, right? So the time of our promise will always be inside me somewhere. I'm sure of it.
Ava: Yeah, I think you're right. Okay, it's a promise.
Laval: May our hearts be our guiding key.
They hugged her and went to the Train
Ava: A Promise... Hmm... Laval, Happy, Shu, some of your friends from their worlds are deep in the shadows of your heart and I won't be able to find them. But don't worry. You made another promise to someone who you could never replace. They your light. The light within the darkness. Remember them, and all the people lost in the shadows of your heart will come into the light.
Laval: Another promise.
Ava: Look at the Good luck Charm, the Crystal Orb and the Ring, I put some magic's in it when you arrived here- But when you though of them just once, it went back to the way it was.
Laval, Happy and Shu look at their Good Luck Charm, the Crystal Orb and the Ring to remember all the People they meet, and now they left Daybreak Town
Flashback has Started
Luxu: The Gazing Eye?
Master of Master: Uh. It"s not what it's called.
Luxu: Oh, what then?
Master of Master: Hm, actually, no name.
Luxu: No Name.
Master of Master: Well, "gazing" or not, that keyblades does have an eye in it. My eye, to be exact.
Master of Master: Oh, you think that's "gross." Do ya?
Master of Master: Yeah, sure. Anyway, about your role. You need to pass down that Keyblades to your apprentice, when they him to his, so that my eye can see the future.
Luxu: So the Book of Prophecies...
Master of Master: Bingo! The fact that it exists is proof of your success! That means you've trained a worthy apprentice, passed down that handsome Keyblade, and fulfilled your role! Congratulations!
He clap his hands
Master of Master: What's the matter? Come on, you did a fantastic job! At least smile a little!
Luxu: But I haven't done anything yet...
Master of Master: Good point. Guess you better get started then! Unfortunately, you'll have to go alone from here on out. No Book of Prophecies to keep you company either. I can't have you causing any temporal paradoxes. But, hey, we both know you'll do just fine without it, right?
Luxu: Do I really have to go alone? What about the others?
Master of Master: Minor details, so don't sweat it. For now, you, that Keyblade, and...
He carried this box
Master of Master: This box need to stay out of sight. Just watch with your own eyes- and my eye, of course- as thing unfold between the others. Then when the time is right, go off and do your thing.
Luxu: What's in it?
Master of Master: It's a secret. And, well, you see... The thing is... You can never, ever open it.
Luxu: Great, now I really wanna know.
Master of Master: Ah, all right. I'll I dulge you. But this secret stays between the two of us, and you have to promise never to open the box.
Luxu: I promise.
He whispered to him
Luxu: But why?
Master of Master: You'll see.
Luxu is far away
Luxu: May my heart be my guiding key.
Laval and his friends are walking down the road with their new outfit that Ava gave them
Cragger: Well. We could go to somewhere. We miss Tino.
Laval: We gonna find a place for us to stay.
Eris: But, where can we find a town where we can help the people and train us?
They know it will take to long and then they saw a town far away
Laval: A town!
So he went off
Laval: Guys, let's go!
They heading to Radiant Garden
Shu and his friends are heading somewhere with their new outfit that Ava made
Marumaro: What do we do now?
Shu: We need to stay somewhere else.
They know it will take to long and they saw a town
Kluke: What's that? A town?
Zola: It is.
Shu is going to Radiant Garden
Shu: Let's go!
They went off to Radiant Garden
The Fairy Tail Guilds are walking down the road with their New Outfits that Ava gave them
Happy: Well. What do we do now?
Natsu: We got to find someone who can trained us.
Lucy: Where will be a location?
They know it will take too long and then they saw Radiant Garden
Gray: What? Is that a town?
Erza: Yes. I wonder what that town is.
Natsu went off
Natsu: Come on!
Happy: Aye, sir!
They went off to Radiant Garden
Reconnect. Kingdom Hearts (Three Stories)