Toaru Majutsu no Index - Volume 21, Chapter 5: The Complex Game Board that is a Battlefield. Enter_Project.

As monstrous invaders ravage the world, Ryzen Kael— a man shattered by a tragedy ten years ago— faces his final moments. But just as death closes in, a mysterious system awakens within him, offering a path beyond his limits.Now, with nothing left to lose, he steps into a dangerous journey of survival and power, defying fate and unlocking abilities beyond imagination. Follow his rise as he challenges destiny itself, carving his name into history!Author's other storiesThe Unrivaled Holder: Rise of the Dragon Monarch - 3rd Season Ongoing

The MC entered the body of the An family eldest son, An Ziran, an arrogant 16 years old boy who weighed 78 kg (~171-172 lbs), who only knew how to eat, play and sleep. Seeing his current body, An Ziran decided his first priority was to LOSE WEIGHT!

In the 5th year of Konoha’s founding.The battle between Hashirama Senju and Madara Uchiha at the Valley of the End had come to a close.In order to treat his elder brother’s injuries, Tobirama Senju resurrected a medical ninja from ancient times, hoping that this individual could prevent the injuries from shortening his brother’s lifespan.This medical ninja’s name was Emiya Shigen.

With a father as strong as the highest heavens themselves, Gravis wasn't required to step into the cold and ruthless world of cultivation. But when Heaven used him in a scheme to get back at his father, Gravis realized that he needed strength to gain true freedom.

As long as he remained his weak self, he would always remain beneath Heaven’s oppression. Only true power brings true freedom. To gain strength, Gravis ventured into the lower worlds to start his cultivation under true life and death tempering.

Only a strong will, which had been forged in striving for every resource available, would allow him to reach the peak. Heaven’s strongest weapon was Lightning of Divine Punishment, and only if he made this weapon his, would he have a chance.

So, to overthrow Heaven,

Lightning Is the Only Way!

Yet, the path to power is painful.

Not everyone reaches the peak.

But Gravis will!

No matter how much pain he feels along the way!