Embers Ad Infinitum - Chapter 4: Rumors

Utsuro no Hako to Zero no Maria, or The Empty Box and The Zeroth Maria, tells the sinister story of Kazuki Hoshino, who is almost madly attached to his everyday life, and his antagonist Aya Otonashi, who suddenly transfers into his class—for the 13,118th time. She majestically announces to “break” him, without paying heed to anyone else around them.

A skilled but unfortunate modern-day assassin was killed in a freak accident. However, he soon found himself summoned to another world by an evil wizard, who had him possess the body of a boy as an experiment. After successfully planning the evil wizard’s downfall, he used the wizard’s body as a springboard to gain influence and power in his new world.

- Description from Novelupdates

A back-to-basics(?) monster evolution novel.

Time back to 1981…

This year, the famous President Ronald Reagan officially took office as President of the United States…

This year, the world’s first personal computer officially appeared, and the era of Internet technology officially kicked off…

This year, the ten-year stock market crash has once again come to Hong Kong, the future Asian financial center, and an international metropolis alongside New York and London…

This year, the Cold War continued, the contest between the world’s two superpowers, the polar bear and the bald eagle, still has no winner, and peace is still far away…

This is the best and worst era…

It was also this year that he came…

- Description from novelbuddy