if this story should be in a timeline with the Kingdom Hearts game, then this would start right after Dream Drop Distance. so you could call it a kh3 story.
I won't follow Sora, Riku, Kairi or any other keyblade wielders, only if they are around the main character in this story: Lea.

Enjoy and please don't steal the picture I made for this story.
and none of the characters or worlds belongs to me, it belongs to Square Enix and the Kingdom Hearts universe

_

When he had stepped in, to save Sora from Xehanort's grasp, he had never expected him being on their side. But he was there and stared at him with no emotions or recognition. All there could be seen in those yellow eyes were an indescribable coldness. Had that really been his old friend there had looked at him…. or was it Xehanort who looked at him through his friend´s eyes? Have Xehanort trapped Isa inside his own body? Forced him to become a vessel? Or has Isa freely chosen to become one of the vessels?

Inside a middle sized house in Radiant Garden, laid a man with striking spiked red hair on a bed, staring up to the ceiling as he have been doing for hours. This was Lea, the human of the Nobody known as Axel and almost a newly initiated keyblade wielder. Lea has so many questions about what happened that day but no one could answer them… only one could. And that person had faded away like all the other vessels inside the room Where Nothing Gather.

Only Isa could tell him the truth.

Lea sat up, still with the many questions in his mind. He got out from the bed and went over to a window where he could see the rebuild gardens of his home world. It went slowly but Radiant Garden looked more the place he knew as child. However, he hasn't done much of helping the Restoration Committee in rebuilding Radiant Garden back to its former glory. Lea has spent most of his time training with his new Keyblade, named Reaching Flames at Merlin´s. He has finally been able to summon it properly, but he still wasn't in the same league as Sora and Riku.

Those two has already gone out to the other worlds once again, training and searching for a way to stop Xehanort's plans. Lea wanted to help, but he knew that he wouldn't be much help for the moment. He still haven´t mastered wielding his new weapon and could still only take down smaller Heartless. There was no way he could defeat one of Xehanort's vessels without getting killed in the progress.

And he didn't really have the time to die, he still have to save his friends and bring them back to this world.

Still, there was someone he wanted, more than ever to confront. From a distance past, he was his best and closest friend. In the Organization, he was his worst enemy and now… he was a vessel of Xehanort.

"Isa, why?"

Of course he couldn't get an answer from the thin air he asked. Lea sighted and left his room, not at all bothering taking on the black cloak. He hasn't been wearing it for weeks and didn't really see any reason wearing anymore either, his dark portal ability has faded away and now he couldn't even make a small one. Yin Sid had told him it was best he used a Gummiship as transport instead, it may be slightly slower, but using a Gummiship was safer.

So he has more or less discarded his former Organization cloak and begun on wearing ordinary clothing. Today he had a white sleeveless jacket with black pockets and markings around the shoulders, on the right side was a small flame symbol. Underneath the jacket, he had a reddish orange t-shirt. His pants were sand-brown and did have slight similarities to his favorite when he was a kid, except these weren´t baggy. His sneakers were dark red with white makings on the sides. He would have worn his favorite scarf as well, but he haven´t been able to find it. He lost it the same day he and Isa lost their hearts inside the castle; it probably got destroyed when Radiant Garden was overrun by Heartless. Quite the pity, he liked that scarf and it's not like he could buy another one for it was homemade by his mother.

Lea did often wonder why Isa has been there with Xehanort, but for now he have to train with his keyblade and get stronger. He did not only train in Radiant Garden, he often trained at the old Keyblade Master; Yin Sid´s tower alongside Kairi who as well was under keyblade training. He and Kairi did surprisingly quickly become friends and after a training session he told her something he quiet for a while wanted to tell her.

"Kairi, do you remember your home?" he dismissed his keyblade and turned around to her "the place where you really came from?" Sora had once told him that Kairi wasn't born on the Destiny Islands, but came from another world.

the young girl shook her with a smile "no" and asked with a titled head "why?" this wasn't the first time she has been asked these questions, but it has mostly been Sora and Riku who has been asking.

Lea turned away from her, a little unsure of this. "It´s just…" he wasn't even sure that little girl he met as kid was her, even he most admit they have quite the similarities. "I think we once met, when I was a kid"

Kairi did not speak; she simple looked at him with pure blue eyes, waiting patience for him to speak. It was kind of funny, for when she looked at him, he gets the feeling that someone else he knew sometimes did the same. but that couldn't be…. he shook that quick thought out of his head and said as he scratched the back of his neck "I remember a little girl, sitting in the garden and picking flowers. She always had her grandmother around and…" he sighted, here goes nothing "when I look at you, I see that little girl."

"Did you sense it as well when you were a Nobody?" she asked him calm; even he could hear she had a slight nervous clang in her voice. She too has become nervous, for when she was with Axel inside the darkness, she had got a weird feeling that she knew him, from a distance past. She had almost asked Axel about it back then, but another Nobody had interrupted them and taken her prisoner.

Lea looked away again with crossed arms, thinking past to those short moments with Kairi as Axel. After a few moments of silence he finally replied "no, I didn´t. it´s first now I have been getting these- I think you can call them flashbacks" he said with a frown, not sure what else to call it.

Kairi gave a small laugh from his reply and walked over to him. Lea eyed her calm even he most admit he was a little tense, for these training sessions was pretty much the only times they saw each other face to face after that kidnapping incident. "Tell me more, please?"

He smiled down to her, but he didn't feel like telling about the past outside the Mysterious Tower. So they went to Twilight Town, here Lea told her his better memories about Radiant Garden, before it fell into Darkness. Kairi almost wolfed down his stories and only once or twice asked deeper into the details and it seems the more he told, the more she seems to remember that place.

"You know, I remember something. Something there never happen on the islands" she suddenly said.

Lea eyed her with a raised brow, not sure it was because of him she suddenly remembers or she always had this memory.

"what do you remember?" he asked curies and added with his cheerful smile "don´t leave me hanging"

she laughed at him, but did tell "well, I remember a boy, he was very quiet around strangers but when he spoke he sure had a large amount of long words for a boy in that age." she hesitated but said "I think… I think he was my friend, back then"

that boy she told about sounded oddly familiar, better be sure before jumping into conclusions "do you remember how that boy looked like?"

"Well, he had grey hair. long bangs there covered his right eye" she showed him by putting her right hand over the right side of the face "just like this, and he had a white cloak— Lea what is so funny?!" she pouted when the red haired man suddenly began laughing hysterical.

"s-sorry" Lea laughed and tried unsuccessful getting a grip on himself. He recognized that description and found it hilarious that such a serious book-worm has been friends with this cheerful and somewhat naive girl "it just; I know that guy" he continued laughing "how come he and you could became friends? All he do is having his nose stuck in a book"

Kairi didn´t answer, she just stared with a shocked look in her blue eyes "you know him?" then she realized he just have made fun of her long distance friend "hey!"

Lea just chuckled but turned once again serious when she started asked "can I meet him? see my birth place? meet—"

"whoa easy there Princess, did you forget you´re under training?" he stopped her before she really got started on her waterfall of questions.

She´s almost worse than Roxas.

Lea felt a sting in his heart just from that quick thought. Man, he missed that boy and his wave of questions.

"Better ask that old Keyblade master before you do anything rash.." He said to her and added with a confident grin "something I would have done in a heartbeat"

she chuckled from that reply but admitted she better should ask Yin Sid if it was alright to leave this world. she thanked Lea and went back to the train there would take her back to the Mysterious Tower.

Lea watched her leave with a smile but it faded when she was out of sight and with a long sight, he looked up to the sky. His eyes turned to the clock tower, the place he, as Axel would sit and talk, laugh and having ice-cream with Roxas and… wait, has there been another one with them? He turned his head down again with wonder, this wasn't the first time it has happen. "…there was… someone else…" he muttered in realization, but no matter how much he tried, he couldn't picture or give a name to this third person.

However, his deep thoughts were broken of a familiar sound, but he couldn't say he liked that sound anymore. He turned around to the newly open portal, ready to summon his keyblade. His narrowed green eyes wide in shock when he saw who the person there walked out was: it was Isa.

"Isa" Lea said in disbelief and somehow also with happiness, even Isa mostly now would try and kill him.

the broad man with the pale blue hair and scarred face looked at him with the again dull expression. He summoned his claymore without a single word, which was quite odd. Isa always enjoyed mocking him in his friendly kind of way. Heck! even Saix always mocked him although the friendliness had been long gone.

Lea did not like this silence treatment and asked taunting "hey Isa, cat's got your tongue?"

No response, even Saix would have made a response on that. Lea snorted and said more in matter of fact than in taunt "Xehanort´s really got you messed up." seeing his friend, like this… it just hurts.

"snap out of it Isa!" he yelled at the man but all he got was almost getting a claymore in his face. Lea dodged the attack the last second and landed on the asphalt again. he turned to the other man "are you really going to let them control you?!" he jumped once again away from Isa´s attack, even that last one he was forced to summon his chakrams to shield the feral attack. Just like in the World There Never Was, they stood with their weapons locked together, face to face. But this time, Lea was far more chatty and hissed to his opponent "do you really want to be Xehanort´s loyal puppet? His lap dog?!"

This time he saw a change in those yellow eyes, he saw anger. And no surprise, Isa hated being called those things.

"fight it Isa!" Lea cried to his friend, but two seconds later. He found himself slammed up against a wall with Isa´s hands around his throat.

"I´m no one's puppet" Isa finally said in a dangerous low growl and glowing yellow eyes, close to go berserk. Lea has sure pushed the wrong buttons this time but at least Isa was now talking.

"really?" Leas asked through what little air he could get from the tight grip Isa had around his neck "then why is it you are on their side?"

Isa did not answer, but he did not have to.

"he has you in his strings, and you blindly allows him doing your every move" Lea wheezed down to the blue haired man. Lea laughed humorless or at least the best he could with the very limited air he could get "you have become his puppet"

Isa sneered and tighten his grip around Lea´s neck "give me one good reason why I shouldn't kill you. Xemnas wasn't the one who turned his back on me, he wasn't the one who kept meddling, forgot the promise we made in the past!"

the past… yes he remember. They both planned to overthrow Xemnas and worked on a plan of doing so, he thought their friendship would hold but… even back then, Saix wasn't the friend he remembered.

Lea´s visions darken from the loss of air, but in that second. He got a memory, it wasn't of when Axel and Saix was planning to overthrow the Organization and how their before strong friendship would slowly shatter. No, he remembered a past when he and Isa, enjoyed each other company. was close as brothers and helped each other in time of need. It did make it harder seeing Isa acting like this, but… it did remain Lea why he was fighting, why he couldn't give up.

He kicked Isa away and the grip around his throat was released. Lea gasped stroke his hand over the sore neck, then he turned his green eyes to the blue haired who looked slightly surprised at him. "I do remember" he told his old friend and got on his feet "but it´s not the pipe-down dream or promise- call it whatever you want, Axel gave Saix in the Organization" now he just wanted to know that if Saix was all there was left in this man.

"I´m not sure you tried to reach me as a Nobody. you kept reminding me of the past, but it always seems to be the wrong one. I didn't question it, but with my time with Roxas" Lea sat his hand on his chest "I began to remember, remember that we not always has been like this… we were friends once, we ate ice cream, laughed and did all kind of stupid stuff together" his silence for a moment but then he glared over to the other man who looked like Isa but, those yellow eyes "that made me question our goal." back when they were kids, Isa´s were different. He was a true friend, his closest friend.

"Isa, do you remember? Back then, your eyes used to be blue and you used to be more carefree, and could take a joke. But now, all I see in those eyes are Xehanort!"

Isa eyes flashed down to the ground, and for the first time since the beginning from their battle, it looked like Lea finally got through. The red haired took a step towards him, refusing to give up. he did not want to lose him! he won´t allow Xehanort to win! "Isa! you can´t let Xemnas- Xehanort control your heart!"

"I´m…. Xehanort?" Isa asked more himself than Lea. Then suddenly he flinched and fell on his knees, screaming in pain.

"ISA!" Lea cried and ran over to his friend, but before he could reach him. Darkness surrounded Isa and he was gone. Lea stopped and didn't see the danger behind him, not before he got hit by the claymore and flew meters away, only got stopped by a wall. Lea shook his head as the world around him span around, when he could look straight again, horror stood before him. Isa stood with weapon drawn, engulfed by darkness and the yellow eyes glared at Lea.

"you have always been a pest in meddling, Axel" he said angry, now sounding more like Saix than anything.

Lea eyes wide, this wasn't how he wanted it to end!

quickly he got on his feet and jumped away from a berserker´s attack in the last second. Saix turned around to him and charged at Lea with a roar.

Instinctive Lea summoned his keyblade and used it as shield but before their weapons even touched, a bright light surrounded them both.

"Isa!"

was his friend so far gone that he wouldn't be able to save him?