Lipstick on an Afterimage

One day, novelist Katsuo Saji unexpectedly finds himself living as the protagonist in a fictional world. But this world has a strange rule: "One character vanishes at a time." When a character disappears, so do all the words that use it. And when a word disappears, everything it represents is erased from existence. For example, when the character "ぱ" (pa) vanishes, "パン" (bread which is "pan" in Japanese) disappears too. When "ゆ" (yu) is lost, so is "ゆうこ" (Yuko), Saji's eldest daughter. As one thing after another fades away, the boundaries between reality and fiction start to blur.

(Source: Kadokawa)