Once upon a time, there's an ordinary man who lived in a peaceful world. A planet called earth with 7 continent and 193 countries. Everyone could do something they want to do without any hindrance.
He is finally reach 28 years old and currently working in a ordinary company. Doing office work, 9-5 and 6 times a week. Completely ordinary until one day, he died by getting hit by a car.
He thought that's the end and succumbed to the ethereal dark and calmness. Then suddenly there's something waking him up even though he can't feel anything. A soft feeling like hand slowly moving him, asking him to wake up from a long dream. When he opened his eyes, unfamiliar ceiling greet him. A apartment ceiling, no something more like a suite as huge ceiling, the details and furniture around his room looked expensive. At first it was confusing and after a long thought on what happened. He got to know that he got transmigrated into the novel he used to read. A typical harem novel with overpowered protagonist and harem. And he transmigrated as one of the extra who didn't do anything even though his family are rich.
A new world filled with adventure, excitement, magic, and fantasy. But he doesn't want to get involved in any of that. He wants to enjoy his new life. Do something he can't do before. Travelling across the world, eat all kinds of foods, learn magic, learn martial arts and everything new.
But everything didn't go as he planned. A few years later, this beautiful world got attacked by an entity who claimed to be a god. The sky got ripped into half, a enormous eyes preying on us. Then the eyes disappear and a huge shadow spawn at the middle of cracked sky. A humanoid figure emerge from it. A god with evil plan. A plan to destroyed this world and no one knows why?.
The protagonist of this world try to fight but even the overpowered protagonist got defeat in one hit. Then the world got split in half just with a mere hand gesture from god. Desperation and despair crawling like crazy inside of him. Maybe, maybe there's a reason he got transmigrated there. Maybe, It's all because of his abilities, adaption. Using that abilities, he tried to fight god. Days turn into month, months turn into year, year by years. Finally he able to kill god.
The world that already destroyed, split in half and deserted. No one survive except him and one more person. He able to only save one person but his ego screaming at him that he actually able to save more but when agony trying to devour him. A new abilities came to him. A chance to change everything.
But with one cost, his current abilities, adaption will be erased. In exchange for new abilities which is RESTART. Another broken abilities that allow him to start back from the beginning countless times.
Its doesn't matter if he doesn't have adaption anymore. He knows this world, everything that happened and everything that he can take advantage off. Even it's may be hard to fight god without adaption. There's another way to use even though it cost something valuable.
Without any second thought, he accepted his new abilities and he goes back to the day he got transmigrated. A familiar ceiling greet him and everything inside give him a nostalgic feeling.
This time, he completely changed his way of living. Instead off enjoying life like before, this time he was training, exploring place to find something useful, goes to the academy where the story of novel happened.
He live a new life. He doesn't care any butterfly effect. The only things he care is in 6 year, the god will ripped the sky and did the same things as before. But he doesn't realize, the things he did change so many things,plot and story.
The protagonist and heroine started noticing him. He grow stronger at abnormal rate. Even without adaption, he showed that talent and hard work were able to make him stronger. Stronger that protagonist but not strong enough to overpowering god.
At the end, he still able to kill god but he only able to save 2 people. One person was the same as his past and another one was one of the heroines. He can't accept it. He RESTART for the second time.
This time, instead of 2 people. He saved 10 people. 2 of them was the same as before and another 8 consist of one heroine and 7 civilian.
( Total heroines inside the novel were 5. )
His ego screaming at him that he didn't give his all and he can do better. So he restart again, again and again. From 2 people he saved, it turns to 10 people. After 10 people, it turns to 100 people. From 100 to 1000. From 1000 to 10 000. From 10 000 to million. From million to billion. Billion to trillion. From one to everyone, finally he saved everyone at the end but not everyone.
There's one more person he unable to save. He failed to save himself. He too strong that he forgets that he was weak. And that burned him. He may saved everyone but there's no one to save him or he thought so.
When there is transmigrator, there is regressor.