Moto Sekai Ichi'i no Sub-chara Ikusei Nikki - Chapter 16: Flashback

Thirty thousand years ago, the Heaven Fighting Race who called themselves “Gods” invaded the Spirit Realm. Hundreds of races rose up in resistance, but ultimately suffered a crushing defeat. The Human Race was the first to concede, and the rest of the Hundred Races soon followed in succession.

“Destiny is a matter of Choice not Chance,

It is not a thing to be waited for but a thing to be Achieved”

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The story sets in a mana blessed world, Planet Vermillion, where every being possesses a System.

At the edge of his life, Zero, a man without a System, finally loses everything and embraces his death with a tired yet relieved expression.

As if by fate, the owner of the system approaches Zero through a screen and gives him a chance to connect with the System, however Zero denies it in exchange for a chance to change or undo all the mistakes he has done in his life.

The owner of the System accepts Zero’s wishes but at a certain price and sends Zero back into the past.

Still without a System, but with the knowledge of the future and various skills honed over the years, Zero begins his new journey to change everything he could.

Save everyone who needs to be saved and kill everyone who needs to be killed.

However, the more he moves forward, the more he realises that the ‘truths’ which he had known in his previous life are much more complicated than what they seem.

Balancing his previous beliefs and the new found mysteries that could shatter his perspective, he still keeps moving forward despite things getting more chaotic with every step.

As if fate itself wanted him to fall, an unknown disaster approaches him from behind and a familiar screen comes in front of him

[Ummm… Zero. It might be a bit late but… Looks like I have messed up big time]

Inexplicably, she had crossed over to the end of the 1970s and was thrown into the mountains. Fortunately, she is rescued by a handsome soldier. Only later does she discover that Brother Soldier is actually the unlucky male supporting role of a historical novel. He was used and deceived by the heroine in various ways and finally dumped on the grounds of the progressive new era not supporting arranged marriage.

Damn, will such a good Brother Soldier will still end up like that in the future? If the heroine doesn’t want him, then step aside and let me have a go.

But how will we live in a time that lacks modern food and clothing? Hey, I bring something different, now I can guide this male lead to be well-fed and make the heroine get mad.

- Description from Novelupdates

She had a dream: the world was brimming with light. Family. School. Friends. Trains. Buses. Movies. Books. In that world of light, she grew into adulthood… and at the very end, in a white room, she fell into darkness. She awoke from the dream to find that she had become a demon. In the demon world, she lived a carefree life until she encountered a powerful being.