Kyoukai Senjou no Horizon - Volume 7B, Chapter 43: Considerate Boys Above and Below

A failed investor from 2017 got drunk and woke up in the 1980s. China is just opening up, and the economy is blooming. There is also the dissolution of the Soviet Union, the bursting of the Dot-com bubble and other financial crisis. He used his knowledge of the future and slowly build up his empire.

- Description from novelupdates

A mysterious natural phenomenon caused the Earth to be plunged into darkness. The world turned into an endless bloody chaos and mankind is on the brink of extinction…

As a cultivator, Lan Tian never expected she'd been hurled back to the 1970s countryside!Suddenly stripped of her powers, she's surrounded by mud - brick houses and farmland. Facing farming to social quirks with no modern conveniences, she relies on her cultivator's wisdom and resilience.

Only a pure maiden can have a privilege to make contract with a spirit.

In Areishia Acadamy, maidens from noble family were gathered there, giving them an elite education to become a spirit contractor. A boy Kamito, by accident he peeped on a girl, Clair, who was taking a bath, and he even made a contract with spirit that she wanted.

Kamito was actually an irregular male spirit contractor, which should not exist.