Kami-sama no Memochou - Volume 8, Chapter 3

In this story, a regular guy from our world becomes a young Main Branch heir of the powerful Hyuga clan in the Naruto world.He's primarily interested in gaining more power and doesn't care about right or wrong. He uses his knowledge from Earth and the Naruto show to get ahead, using his creativity and intellect to the utmost.As he tries to become more powerful, we see sides of the Hyuga clan and ninja world that weren't shown in the original Naruto story.He looks into the secrets of his ancestors, the Hyuga's eyes, and how ninja politics work, finding out things we never knew before and that the original author left unexplored.However, gradually, along the way, he also meets new lovers, friends, subordinates, and enemies and challenges how things are done in the ninja world - and also tries to unify it in the process and bring real peace around.

"There is a thin line between poison and medicine, and I shall make you dance on it!"

What was originally an ordinary day, suddenly became a historical turning point. Enormous, mysterious Cubes appeared all over the world without warning and as if Judgement Day’s spears, inserted themselves into the blue planet.

From inside the enormous Cubes, endless streams of monsters gushed out alike raging tides, utterly defeating the unguarded armies of each state in the blink of an eye.

In order for humanity to preserve its final embers, the heads of states issued orders of retreat, to no longer attack the Cubes but rather to cling to remote cities, which they turned into self-sufficient survivor bases and around which they built 100-meter-tall Walls of Life!

Many years later, while bearing the heavy weight of history, the first expeditionary force brought back a world changing piece of information. The Cubes possessed exceedingly high intelligence and they regularly transmitted mission instructions to humans nearby. The mission rewards were incredible.

Since then, humans rushed out of the confines of the walls and once more set foot on the wasteland!

- Description from Novelupdates