Avatar the Last Airbender: Deep Waters (SI) (Reincarnation)

Allen floated close to the divine being, an intense pressure encapsulating him, yet he didn't bow.

Allen instinctively knew, he was in HIS presence, and acknowledged it with a respectful nod.

"Thank you for blessing me with such a fulfilling life", he expressed

 "I blessed you with life and free will, child. The circumstances you lived in, were ones of your own making", HE explained

"Karma exists, and you received happiness, fulfillment and satisfaction for the good you did"

"GOD, I killed people. I was an assassin, a mercenary. Was I still a good person?"

"Tell me, who did you hunt?"

"Dictators, slavers, rapists, corrupt people, murderers. The worst scum of Earth"

"I am loving, and I am merciful. The people you killed, hurt my creations", GOD explained, "By killing them, you saved lives, and avenged those they hurt. It was a meritorious act" 

"Making you, Allen, was a worthwhile endeavor", GOD smiled

Unbridled joy filled the man, and he felt at loss for words

GOD laughed, a heavenly laugh

"Child, I wish to reincarnate you into a different world", HE spoke, "you shall receive a second chance at life, should you desire it"

"What world?"

A roulette wheel appeared into existence

"We'll let Chaos decide"

The wheel spun, its pointer landing on some unknown worlds, and some worlds of fiction, he had read or watched before

TICK! TICK! TICK! TICK! the arrow landed on the plate that read, "Avatar the last Airbender"

"Congratulations", GOD waved the wheel away, and in its place appeared a smaller one

"Now chaos shall decide the powers to bestow you with"

"How many?", Allen asked

"Three" 

The wheel spun, landing on [Adaptive Development]

A scroll materialized

[Adaptive Development]: The user possesses a rapid development rate, allowing them to permanently push back their limits when continuously reaching them, whether physical, mental or supernatural

Understanding his gift, Allen waited for the second spin to come to an end

A scroll with the heading [Power System], hovered in front of him

[Power System]: A system screen that displays the user's abilities and helps them tap into the world's power system. The system will help the user master his skill set and display their progress in percentages. It will also issue quests and hand out rewards. Should the Final World Quest be completed, the user shall be presented with a chance to travel to a different world.

As Allen carefully read the description, the wheel spun for the third and last time.

[Bonded Familiar], the arrow pointed. 

Instead of a scroll, a raven actualized. Its majestic form flew closer, and Allen felt the formation of a warm bond with the lovely creature.

"Luna", he whispered, and the raven cawed in acceptance.

"Any questions?", GOD asked

"Yes? How does the [Gamer System] differ from the [Power System]?"

"[Gamer System], lets you view your stats and the stats of others, but the [Power System] does not. [Power system], lets you tap into the world's power system, and displays your abilities, pertaining to the system in percentages. You don't have an [Inventory], [Party] option, [Dungeon Create], [Shop], or skills like [Gamer Mind] and [Gamer Body]. The [Power System] will ensure your and Luna's powers are never copied, cloned, stolen, blocked or mimicked in any way, shape or form"

"Does just existing change the world's future?"

"Yes and No. A world's fate is akin to a river's flow. It will flow in a predetermined path, but you exist outside it. Your actions will be like boulders, slightly changing the water's course, but ultimately keeping the river's flow unchanged. Only by making massive changes too quickly, will the river's trajectory shift into a new path"

"Will [Adaptive Development] grant me immortality?"

"No. It will, however, stop your aging after your 25th birthday"

"What of Luna's lifespan?"

"Luna will live, as long as you do. She'll heal from fatal injuries, resurrect herself to full health upon death, never leaving your side for the entirety of your new life. She is your familiar"

"Can I choose 'not' to do quests?"

"Yes"

"Do you have expectations; you wish me to fulfill?"

"No. You have free will"

"Thank you, GOD. That is all"

GOD slashed his arm and space ripped open behind HIM

"Your journey begins once again", GOD gently guided Allen and Luna towards the tear, "enjoy it"

"I will", Allen promised with great excitement and anticipation.

<<--------------------------------------------------------------------------------- >>

Two blazing souls emerged in her domain. The Mother of Faces curiously stared.

"Powerful and with the potential to live for an eternity", she concluded.

"I intend to carve the most precious and charming faces for you to wear", she said, "treasure them, forever"

<<--------------------------------------------------------------------------------- >>

{North Pole}

Kaya breathed in and out, laying on the birthing bed. Nurses and a healer surrounded her, encouraging her to push again.

Her sister stood to her right; their hands clasped together. She was a calming presence by her side.

They finally witnessed the birth of the one free of destiny.

"It's a boy, and he is healthy and strong", he doctor examined. Slowly, she handed Kaya her child.

She lovingly held her beautiful baby, before losing herself in his vibrant, overwhelming eyes, a kaleidoscope of blue.

Nami, her sister gasped, "His eyes, they're glowing"

"They are"

Her son's eyes roamed around the birthing room and latched onto the healer's glowing hands. They held an intelligence, unnatural for a babe just born.

She caressed his head, and he turned to smile at her. Her boy leaned into her touch, and she cried tears of joy.

"Zerun, his name's Zerun", she announced.

Kaya felt her life slipping away. She knew giving birth would be the last thing she did before leaving her mortal body and ascending into the spirit world.

Sensing his mother's pain, Zerun cried for the first time.

"Don't cry, baby, don't cry", she kissed his forehead, slowly picking him up and handing him over to Nami, "I'm leaving for the spirit world, it's too painful to live in this body. We'll meet again, if fate allows it"

"Take care of him, love him, and teach him. Make sure he bathes regularly, and brushes his teeth before bed", she said, "make him eat his vegetables, and no dating before he's thirteen"

"Okay, Okay", Nami smiled a bittersweet smile

"Don't cry Nami, you can come visit me in the spirit world"

"Should the Ocean and Moon allow it"

Kaya closed her eyes and started to meditate. Zerun stopped sniffling, to observe his mother's ascendence. The birthing room remained quiet. Everyone watched in awe as Kaya glowed blue.

When the light died down, the doctors confirmed her departure.

Nami mourned the passing of her sister and left the hospital with her nephew in arms. Along the way, Zerun fell asleep, exhausted. 

Born during the winter solstice, some ancient spirits noticed the arrival of a powerful soul. Zerun had stormed into the world of "Avatar"