System

'Airbending, Firebending, Waterbending, Earthbending'

'Which one should I choose'

Kain's brows furrowed.

'I guess I should start by eliminating them one by one.'

He put cupped his chin and started pacing around to concentrate on making a decision, 'Firebending seems like the one with the least advantages here. It does offers me short distance flight with the fire and it does provide great attacking power.'

'However, Firebending had extremely little versatility. While it was very powerful offensively it had practically zero stealth usage and there was also the fact that it was very hard to control the fire effectively on a level of someone like Zuko or Iroh.'

Kain face looked like he was struggling with a choice however, 'But firebending does have the sub element of lightning, which was clearly one of the most deadliest techniques in that world.'

After some careful thought he shook his head and sighed, 'But lightning bending can be countered easily by any other firebender. Also firebenders just so happen to be considered the enemy of all other nations.'

'The next one on the list should be Earthbending'

'As an architecture fanatic and engineering student he realized the amount of things he could create and the buildings and houses he could construct'

'However, in the world of avatar, what was most important was survival. Perhaps if it was in the Legend Of Korra he would find Earthbending viable and even a preferable option'

'But the system had clearly stated that he would be sent to the backwards, primitive world of Avatar The Last Airbender, not the world of The Legend Of Korra.'

'In combat and versatility earthbending worked very well. However, the main reason he couldn't take it was because of the essence of earthbending.'

'Earthbending required the user to be headstrong and to face danger head on. I'd prefer to do things with more stealth and finesse rather than head on. Therefore this would be highly impractical for me'

Kain looked back at the system and the two remaining options.

'Airbending or Waterbending?'

Airbending was one of the strongest elements on the list.

Airbending provided its user with flight, ranged attacks and the ability to move far faster than any other element. It even had the ability to directly suck out the oxygen in someone's lung and kill them.

'However, considering that all airbenders had already been wiped out it would raise a lot of eyebrows if I could airbend. There was a very high chance that I could be mistaken for the avatar and hunted down. Even if I wasn't mistaken for the avatar I would still risk being hunted down by the fire nation if they saw me as a threat.'

It would not be good for him if he were to be constantly hunted down by the best the fire nation had to offer. After all, in a war torn world like this, there was no point in making himself an even bigger target.

Also he didn't have a Deus Ex Machina like Aang's avatar state to help him, though he hoped his system would give him something on par with it.

Besides, he already had his eye on the last option left.

'Waterbending.'

As he looked at the last remaining choice he grinned.

Waterbending was the most versatile bending style. Waterbending was based around change and adaptability. With waterbending he could make quick changes to fit his current situation. 

'Besides, Water also has the sub elements of ice bending and blood bending.'

With the use of icebending he could turn his bendable wavy water into a sharp tool for killing.

If he could blood bend an opponent in a fight he would have basically won the fight already. There was no way to stop it unless you could stop it too.

Not only that, but the strongest bender to have existed besides the avatars belonged to the waterbenders, Amon.

'Amon was able to blood bend without the full moon. Not only that, but he could also match up in a fair fight against avatar Korra without once showing his waterbending.'

If Amon could do it, why couldn't Kain? Besides he had a system to help him in his journey didn't he?

Kain's grin grew wider as he clicked on the option that said [Waterbending]

As he clicked on the option the letter on the box changed.

[Thank you for choosing you bending. As the systems job has been fulfilled, it will now shut down.]

Kains eyes widened in shock as he shouted, "Wait, aren't you supposed to be my cheat? Don't you have any beginner starter packs to give me? Aren't you supposed to give me a quest or something?"

The system suddenly turned blank for a second or two as if it was contemplating before it displayed another message.

[Main Quest]

[Kill Fire Lord Ozai (0/1)]

[Master Water Bending (0/1)]

[Defeat Vatuu (0/1)]

[Reward: Returning home]

As Kain read the message on the box, he felt like crying.

'What kind of beginner quest is this? How does it expect me to kill the fire lord? Also, I thought Vatuu was only supposed to awaken in the Legend Of Korra-'

Before his train of thought could finish though, a portal suddenly opened from behind him, creating a deafening sound as it dragged in everything around it.

Kain tried to hold on to the ground to resist being pulled but he couldn't find any way to get traction on the smooth floor. In this situation, all he could say was.

"MOTHERF-"

After his body had completely been swallowed by the portal it closed, stopping the loud sound.

In the silence, a feminine voice talked over the absolute silence.

"Hopefully I've made the correct choice. You are the only hope for us, Chosen."