Shini Yasui Kōshaku Reijō to Nana-ri no Kikōshi - Chapter 111 - Seven Wonders of the Academy (part one)

Yu Shanshan, who has been tyrannical and lawless for 20 years, suffered retribution at the age of 21. She changed from a little ballet princess of 45 kg to a poor and fat one of 90 kg.. Apparently, eating was the most important thing in her life. Her success in losing weight was far away.

However, one day, the father of her child who had disappeared for four years came back. From then on, Yu Shanshan was forced to embark on a diet that was worse than death.

- Description from Novelupdates

“The Shadowx, the name of a warrior who does not have any elemental powers.Fighting those who stand in his way, his goal is still ambiguous. But, the light will be shed on it later after.”“A world which is led by elements, an era in whom humanity took control of the elements which are 4 main elements (Flame, Frost, Shock, Terra).”“A threat known as the dark powers came to destroy this empire of elements which is held by the strongest 3 elemental warriors, The Emperors.”“Even me, I am a warrior named Radiant. Time shall come to reveal everything, EVEN...ME.”

The world was once at war with 10 alternate worlds. This was known as the Concept War and our world won 60 years ago. All of this was concealed so no normal people are aware of this fact in the current time.

After the death of his grandfather, the high-school student Sayama Mikoto is suddenly summoned by the giant corporation IAI. He learns this world is headed for destruction due to the acceleration of the Minus Concepts. To prevent this, negotiations must be undertaken with the survivors of the other parallel worlds so their 10 concepts can be released.

And so Sayama is caught up in the final battle to clean up after the Concept War which left behind so much enmity.

He put one hand on the door beside her head before leaning forward. What was he doing? Trying to intimidate her again?