Yarinaoshi Crank-In

Nekoyashiki Tora is a genius author who can write an entire novel in seven days and is known as "The God Who Creates Worlds." But his true identity? A complete hikikomori in his thirties. One day, when he collapses from overwork, his sister, Neko - a pharmaceutical researcher - administers an experimental immortality drug that she has been developing, making Tora young again! Forced by his sister