Vlad, who had completely forgotten his full name, was the only immortal surviving an end of the Era tribulation.
What is that you ask, well, simply put the world had too many immortals that absorbed it's essence to live forever, so it decided to kill the majority of them to regain that essence hence it used all of it's remaining power to cast the tribulation.
The problem started when few of the oldest immortals interfered to protect their juniors by laying different arrays that started to absorb the essence even faster thus further angering the world. It started killing cultivators, snatching the essence back and increasing the power of the tribulation.
This kept on going for a few centuries before the first few immortals died and the world regained a huge chunk of it's essence back, This in turn increased the power of the tribulation killing more and stronger cultivators and immortals and the cycle kept repeating until Vlad, who was, for this millenia or so, trapped in a natural underground array, was the only immortal left. When he finally left the array, he found that the only type of cultivators left were those that took the path of refining their bodies using the blood essence of different beasts.
He stated to travel and tried to find anyone who cultivated the path of the essence but found all the heritages completely destroyed by, most probably, those fleshy cultivators. This angered and pained him so he started killing the strongest of them to try to alleviate the pain and sadness of losing all of his friends and partners. The remaining cultivators tried to explain it to him but he didn't want to believe that he was the only one left.
After all the anger and sadness came the lonliness. He created his own sect and started teaching many disciples. After a few centuries of teaching and finding some solace he went into seclusion to rest his weary heart. This continued for some time until he realised that no one was able to reach the rank of immortality even with his help. The tribulation for ascending was too tyrannical and completely destroyed everything, including any and all arrays, his own immortal energy and of course the one trying to ascend.
He gave up after a few hundred tries as he noticed that as more time passes the stronger the tribultion becomes. He kept watching as new disciples came and old one died due to old age since they had no competitors. He kept watching as the new friends he made die of old age, their kids, grandkids and preceeding generations died while he was slowly and completely forgotten. His sect destroyed itself from within as he simply watched it happen. Any emotion left in him like anger, sadness and even loneliness vanished.
At this point he simply wanted to end it, so he decided to kill himself and enter the cycle of reincarnation. He himself did not know that he wanted some companionship, he was longing for love and affection, he was starting to get jealous of the mortals.
So he created what he felt was the best and most organized 'help' for his reincarnated self. He didn't know why he created this help and the feeling he had when he created it, rather he didn't even know what the feeling was. Was it some sort of desire or expectation? After creating it he simply called it System.
Looking one last time at this world he felt nothing for, he left the world quietly with no one knowing that the last immortal just died.
What Vlad did not know that after his death the world started changing, the already huge world started to get bigger, like some constraints were finally removed. It started getting bigger and bigger until it suddenly stopped and imploded in on itself, creating something like a big bang. This process happened over hundreds of thousands of years with the planet itself slowly destroying all life on it before its full expansion and implosion. Of course Vlad did not have any idea of what was happening.