Nightblade

In the future, all facets of society are tied into Oz, a virtual world inhabited by millions of users. Kenji, one of Oz’s moderators, was set to begin another typical summer when the lovely Natsuki asked him to accompany her to her hometown as a job.

A massive earthquake ravaged Japan's mainland and destroyed most of Tokyo, sinking three-quarters of it into the ocean. Ten years later, the story shifts to Igarashi Ganta, a seemingly ordinary student attending Nagano Prefecture's middle school.

Nineteen-year-old college student Hana meets a young man who sneaks into her classes for lessons and falls in love with him immediately. They soon start dating.

Ashinaka High School is known for its unique setting: the entire campus is built on an island. Yashiro Isana, aka Shiro, is having lunch with a cat on one of the school rooftops.