X Reader is a term used in secondary creations known as “Yumehon” in Japan. It's a creative genre that depicts interactions between copyrighted characters from manga or games and original characters prepared by the reader (writer).

Depending on the writer, the relationship can vary, such as being depicted as a friendship with an original character or a work depicting a romantic relationship. By introducing original characters that do not originally appear in the work, it is a popular creative genre that can express personalities and behaviors that copyrighted characters do not usually show, without changing the relationship with other copyrighted characters in the same work.

For example, these X Reader books are popular in Meitantei Conan (Case Closed)!

※When introducing characters, it includes some spoilers up to what is currently being aired in the anime. Please be careful!

At times he is Kogoro Mouri's detective apprentice, sometimes a part-timer at the café 'Poirot', sometimes a member of the Black Organization, and his real identity is a public security police officer. He interacts with the protagonist Edogawa Conan from various positions, and while aiming to dismantle the Black Organization, he operates secretly, sometimes as an ally and sometimes as an enemy.

Because Amuro-san has such various roles, in X Reader books, there are many characters in various positions appearing, such as customers observing Amuro-san working at the café, or getting to know him as a client while he is working as a detective.

He is a friend of the previously mentioned Amuro-san from his police academy days and is a professional at disarming explosives. He belongs to the police force but hates the police due to past events, and often argues with Amuro-san, who tries to fulfill his duty as a police officer. However, his character is kind and a bit conceited, but he can't overlook people in trouble. He appeared early in the story and his death in the line of duty was depicted. However, he has many appearances in the police academy edition that later depicted Amuro-san's past.

In this way, Matsuda-san is a very good character, but he exited the stage early. Fans who want to see more of his various forms have created X Reader books. I understand those feelings very well. Matsuda-san is really cool after all~.

He is an FBI investigator and a master sniper. His skills are no less than Gin of the Black Organization, and he has saved Conan in a pinch many times. Because of his incredible combat ability, he is thoroughly marked as a person to be prioritized for exclusion by the Black Organization, and he is currently disguised as a certain person and acting in secret.

In this way, it is a mystery what Akai-san is doing every day, and there are many X Reader books that imagine such days. If I were to become a lover of such a mysterious Akai-san, what kind of life would it be...... I'm certainly curious, and I'm also curious about what kind of X Reader books have been released!