How old is human civilization?
A thousand, no six thousand years?
So why is the human year still in X790?
Due to certain reasons, humanity has been wiped out a few times over the thousands of years. The first human civilization made it to X2050 when they suddenly found a way to reach heaven in an attempt to slay the gods. As mediocre as it might sound to be able to slay a 'god'.
They somehow managed to do it.
The name of the slain god was deleted from history books right before Chronos the god of time rewound the clocks of evolution back to the beginning. This time, they made sure to nip it in its bud at an early stage.
The next civilization was fortunate enough to live up to the year X3002. But humans started scientific mutations on one another before finally attaining hybrid bodies. The notion made the gods anxious and once again... Humanity was eliminated.