Disclaimer: I don't own Avatar

Here's just something that I've been thinking about.

Author's note: As of December 15, 2013, this story is currently being revised and will continue to be updated!

1. I've decided to age them up a bit. Aang and Toph are 14, Katara and Azula are 16, Sokka is 17, Zuko is 18.

2. Yes obviously, Aang will be very different in this story. His decision caused him to change drastically.

3. Heavy Kataangst will be featured in this story. As well as a hint of Zutara. I will not reveal this early on what the end game is. Whether this will be a story of love conquers all or if power truly corrupts entirely and completely. You'll just have to read on!

4. This is not a happy story. So if you cannot stomach those, please turn back.

Thank you and please tell me what you think in a review!

Summary: What if in "The Guru" Aang had chosen cosmic energy instead of Katara? What if he finished his training with Guru Pathik and had let go of Katara? What if Katara and Zuko had more time alone in the Crystal Catacombs since Aang was delayed for a few minutes? What would happen if Aang had gained the unimaginable power of the dark, celestial Aang from his vision? A dark and twisted re-write starting from the season 2 finale, The Crossroads of Destiny.


PROLOGUE

"The Thought chakra is located at the crown of the head. It deals with pure cosmic energy and is blocked by earthly attachment. Meditate on what attaches you to this world."

Aang saw Katara. All he could see was Katara…for so long now even.

Katara waterbending. She moved with grace, beauty and power. Amazingly and completely at peace, completely in control. Face flushed from exertion and eyes shut, a thin stream of water was twirling around her. She was smiling and laughing, eyes so bright and so full.

Katara, simply standing, calling his name with a warm smile. She was wearing the necklace that he had made for her when her mother's had been lost. She still had that necklace. It was very pretty, but it wasn't at all valuable. Of course, Katara didn't cherish it because it was particularly costly, but because it had come from him, Aang made it and that was more than good enough for her.

Katara inches away from him in a dark cave, gazing into his grey ones with her blue…cheeks red, lips anticipating and nervous and then their lips touching.

He suddenly came to a realization. It was all for her.

She was the one attaching him to this world, she was the one who kept him balanced, kept his feet on the ground. How could he have possibly dealt with everything that was thrown at him without her by his side? The Fire Nation, his responsibilities as the Avatar, the world he left behind for 100 years, the loss of the Air Nomads…Monk Gyatso. Without her, he'd be a mess, a crazy senseless mess.

She was all things love, beauty, emotion, hope, strength, passion, and faith.

"Now, let all of those attachments go. Let them flow down the river. Forgotten."

"What?!" startled, Aang blinked at him. "Why would I let go of Katara? I…I…I love her."

"Learn to let her go, or you cannot let the pure cosmic energy flow in from the universe," the guru told him.

"Why would I choose 'cosmic energy' over Katara? How could it be a bad thing that I feel an attachment to her?" he retorted in agitation. "Three chakras ago, that was a good thing!"

"You must learn to let go," Guru Pathik firmly replied.

Aang took a deep breath, uncertain whether he should crucify the old man for even suggesting this, to humor him out of respect or simply and politely reject his proposition.

"I'm sorry," he chose to go with the latter. "But I can't let go of Katara."

"Aang," the guru started, "to master the Avatar State, you must open all the chakras. Surrender yourself."

"I just…I can't do that, I'm sorry. I love her," he declared. "I belong to her," Aang has come to terms with this now, and suddenly he felt heavy.

"Listen to yourself," the guru cried immediately, "you are not hers. You are the Avatar, you belong to the world."

Aang gaped at him, coming to an awareness that everything that the guru had been saying was right. It was a time of war. Enlightenment will help him become a Fully Realized Avatar. It will help him become his most powerful. And the world needed him to be just that. The Fire Nation would not stand a chance against him.

What about Katara? I love her.

He saw himself then, seething with anger, tattoos burning with an intensity of a hundred comets…the Avatar at his most powerful. Everyone ran away from him, they feared for their own safety. Sokka and Toph, and the sandbenders. This was when he had completely and intentionally let his anger take over him. Appa had just been taken and he wanted to hurt the guilty ones.

He felt so powerful, so dangerous, uncontrollable, unstoppable.

And yet Katara stayed with him. She did not run away like the others did. Her safety was not important to her. Katara took him by the arm, and even when he looked down on her full of anger and hate, she enveloped him in her arms and let him stay there.

What if I hurt her? What if I couldn't control myself and I hurt her?

The gentle, affectionate look in her eyes whenever she addressed him combined with her kind smile and warm hugs almost made him consider running off with her and taking her to the skies. He and Katara could be free and alone. They could kiss all they want. They would be untouched by worldly matters, which mostly consisted of bloodshed and war.

He knew it was all too selfish yet he couldn't stop himself from thinking such thoughts.

('I saw you get so upset that you weren't even you anymore. I'm not saying the Avatar state doesn't have incredible and helpful power. But you have to understand, for the people who love you, watching you be in that much rage and pain is really scary.')

For the people who love you…

This was for Katara. He will do this for Katara and for the world that she will live in. And maybe when times are better, when the world is finally at peace, he'll come back to her.

"Okay…I'll try," Aang finally agreed, although still very reluctant, Guru Pathik could tell.

"Good. Now, think of all your attachments and let them go."

Aang entered a weird, surreal state of meditation. He saw Katara's beautiful face in the starry heavens. She was staring at him with two bright ocean eyes, the luminous stars around her can't even compare. Then before he could even fully take in what he was seeing, his world started to spin…the stars too, blurring his vision of them as Katara vanished with a brief twinkle of light. Aang felt guilty as he watched her disappear before him and he caught himself when he started to run toward where she had gone. He knew that thoughts like these were wrong, he knew he shouldn't have been thinking them, but he wished that he could disappear with her as well and leave everything behind.

"Let the pure cosmic energy flow," Aang heard the guru say.

The stars and an aurora of light blinded him briefly. He shielded his eyes from the overwhelming brightness. A moment later, he was above the planet. He was truly amazed at the precession of this dream. Did the earth really look like that from above?

The great light solidified beneath his feet into a radiant bridge. There was a massive, dark entity floating at the end of the path, as if waiting for him, beckoning him.

It was himself.

The entity's airbender tattoos and eyes were gleaming a bright white. In his awe, Aang carefully walked towards it. His tattoos began to shine with an overwhelming white light as well, brighter and brighter the nearer he got to the entity.

The giant, dark Aang descended, a sphere of cosmic energy shimmering between his fingers. Aang was immediately drawn to the power, like a moth to a flame. Enclosed within the sphere, he felt the power surge through his veins, all the power in the world offered to him on a silver platter.

Avatar Aang is the Supreme Being, above all human kind, the most powerful individual in the entire world. It was so invigorating, so intoxicating, so electrifying that it hurt.

A vision came to him suddenly, then a high-pitched cry of distress…It was her, it was Katara! Chained to a wall, she was screaming at an unseen captor, wrangling the chains about, and demanding to be freed. Aang's immediate reaction was to leap from the hands of his celestial spirit. The sphere of limitless power vanished from its fingers.

Aang ran away from the dark being, wanting to get away from it all and back to his world, to Katara. Behind him, the Great Spirit fell to oblivion and faded away with his absence. The path Aang was on began to fade rapidly, until it too, completely disappeared dropping him plunging and screaming towards earth.

"Katara is in danger! I have to go!" With airbender speed, Aang managed to run a decent amount from the guru before Pathik could even react. He slid down the roof of the tower and readied himself to jump.

"No Aang!" the guru cried just before Aang left. "By choosing attachment, you have locked the chakra! If you leave now, you won't be able to go into the Avatar state at all!"

The Avatar was at the very edge of the roof. He desperately wanted to throw himself across the temple and back to Ba Sing Se but he found himself helplessly stuck there and unable to move. He slowly turned around to face Guru Pathik, eyes locked on the heavy stone floor. The guru quickly saw how tormented the young boy was and was sympathetic with the choice he must make now. He could only hope that Aang makes the right one…the fate of the entire world, billions of lives, is much more important that of an individual's.

"The world needs you, Aang," the guru sullenly told him.

"But Katara─"

"Why is her life more important than that of another's?" The guru railed before Aang could finish. "You are the Avatar…you must be objective, practical, fair, and detached. It is your destiny."

('There's a right way to do this. Practice, study, and discipline.')

"You're right," Aang gruffly muttered to himself. Katara wanted this for him. "I'll do it, Guru Pathik."

The guru sighed his relief. "You made the right choice, young Avatar. I'm glad."

('A hundred years! I can't believe it.'

'I'm sorry, Aang. Maybe somehow there's a bright side to all this.'

'I did get to meet you.')