The sun was dying.

The sun was dying, and humanity would die with it.

How could this be? The sun had enough fuel to survive for the next 5 billion years.

The distant, far-off future, a time where technology would’ve been advanced enough, a time where we would have had a solution.

A time that nobody could imagine, but yet had faith in.

A problem left to the future「us」.

But here it was, right before us. And so we asked 'how could this be?’

We were not mistaken. The sun did indeed have enough fuel to last 5 billion years.

But, there was something that we forgot to input into our computer models.

The sun produces energy through nuclear fusion, turning hydrogen into helium, and releasing massive amounts of energy as a byproduct. And the amount of hydrogen that it had could keep it going for a long, long time. But helium is denser than hydrogen. And as the sun turned more and more of its hydrogen into helium, its density rose, and its volume fell. Not by a lot, mind you, not even a tenth of a percent.

Yet, this had been enough to influence Earth. The change wasn’t obvious at first, even the minute increases from global warming were enough to offset it. As years passed, the warming caused by greenhouse gases slowed down. People attributed it to the various policies enacted to prevent global warming and felt success that they, united as a race, could do absolutely anything and looked forward to the day where the climate finally stopped increasing totally.

And that goal was reached, in a few decades. Global warming was over - temperature change was stopped at last!

But it didn’t stop. It kept dropping, and global warming turned into global cooling. Even so, most people thought that the Earth was simply dropping back to its original temperature, the state before global warming had started.

Heating bills rose in many parts of the world, and more people began to wear thicker clothes. Nobody thought it was a problem, winter jackets and scarves even became fashionable.

But, as years passed and temperatures kept falling, people started worrying. Perhaps if it was seen as an environmental problem, something could’ve been done. Instead, it was widely recognized as an economic problem.

As the number of electronic devices increased exponentially, combined with increasing demand for heaters, energy usage skyrocketed. Prices for oil and natural gas rose, and people turned towards renewable energy for a solution. During the global warming crisis, however, the locations where wind speed was the highest, where solar panels would be the most efficient, and where rivers were the fastest had all already been taken up. The areas left could only generate a tiny bit compared to what humanity required for its growth.

As prices kept rising and temperatures kept dropping, many countries turned to coal, and even to biofuels in order to sustain their economies. Eventually, sparks appeared, conflicts arose, and arguments turned to violence as nations began to fight over dwindling resources.

Food, clean water, electricity.

Such basic necessities were beginning to run out.

By the time humanity began realizing the severity of this issue, it was too late. The various divisions and alliances had already expended all of their resources in fighting one another and building up their armies and militaries.

Perhaps if they had tried to cooperate instead of competing, they could’ve found a solution. But, humans are humans, and what had been done was done. What 'solution' could be created with the meager supplies they had left? Most people only had a tiny bit of food and the clothes on their backs.

At that time, humans could be categorized into three major groups.

Those that had no more will to live such a life, those that wanted to live and survive, and finally, those that wanted 「 humanity」to continue on.

The first group died off quickly, obviously, leaving behind the other two, which were named the United Coalition and the Paragon respectively. One, which was military based, and the other, which was technologically based. Two opposite goals, two opposite viewpoints, but fighting over the same land and resources.

People outside of these two groups were practically nonexistent - if you wanted to live for long, you joined one of them. Between the networked, steel houses of the Federation and the underground bunkers of the Coalition, more people chose to side with the latter. After all, how many would be willing to fight for the 'survival of humanity' over their own lives? Death was also very common, whether it was from the minefields and machine gunners of the Coalition, the steel tanks and snipers of the Federation, or the always looming threat of freezing and starving to death.

And so, humanity continued its armed conflicts. One fighting for the people of「today」. And the other, fighting for the people of「tomorrow」.