8位：The Mage Orphen

出典 : Amazon.co.jp

Battle Fantasy by Yoshinobu Akita, published by Fujimi Fantasia Bunko and TO Books since 1998.
It is illustrated by Yuuya Kusakawa.
As of October 2019, there are 20 volumes of the main story “Hagure Journey” + 13 volumes of the short story “Reckless Edition” + 10 volumes of the new series.

Both the serious main story about the days of battle between Orphen, a necromancer from the Fang Tower, and his friends, and the reckless version, which depicts a brief period of peace in a lively and fun way, have become popular, and the series has become a mega-hit with a total of 12 million copies sold.
The series became a mega-hit, selling a total of 12 million copies. It has had a great influence on later fantasy works based on magic and witchcraft.
It has been made into an anime twice between 1998 and 2000, and will be re-animated in the winter of 2020.

7位：Is It Wrong to Try to Pick Up Girls in a Dungeon?

出典 : Amazon.co.jp

This is a fantasy novel by Fujino Omori Sensei, published by GA Bunko since 2013.
It is illustrated by Zuhito Yasdas-sensei.
As of October 2019, 15 volumes of the book plus 12 volumes of the outer story, Sword Oratoria, have been published.

Set in the labyrinthine city of Orario, which has a vast underground labyrinth, this adventure story follows the growth of Belle Cranel, a young boy who joins the Goddess Hestia’s Familia and interacts with other adventurers and gods, and the series has sold over 12 million copies in total.
An anime adaptation of the series began in 2015, and both the book and the outer story have been adapted to film.
The third season of the main story is scheduled to air in the summer of 2020.

6位：That Time I Got Reincarnated as a Slime

出典 : Amazon.co.jp

This is an otherworldly summoning fantasy from Narou, published by GC Novels by Fuse Sensei since 2014.
It is illustrated by Mitsuba-sensei.
It’s a story about a main character who has been reincarnated as a slime in another world and uses his characteristics and reincarnation bonuses to rise up and become both an individual and a group.

As of October 2019, the book has been published to volume 15.
The comic book version, drawn by Dr. Yasuki Kawakami, has been an explosive hit, and the series has sold over 14 million copies in total.

It was made into a TV anime in two cool seasons from the fall of 2018 to the winter of 2019, and thanks to that effect, the original sales of the series have also increased significantly, and it proudly ranked No. 1 in the 2019 first half of the year (Oricon) for the sales rankings of novels.
A second anime season is currently in production.

5位：Magical High School underclassmen

出典 : Amazon.co.jp

It is a battle fantasy from Narou, published by Dengeki Bunko from 2011 by Tsutomu Satou.
It is illustrated by Kana Ishida-sensei.
As of October 2019, there are 30 volumes of the main story plus two spin-off volumes published.

The story revolves around the struggles of the students of Magical High School, centered around the brother and sister of the strongest underdog, Shiwa Tatsuya (Shibata Tatsuya) and his sister Miyuki (Miyuki), who are known by the nickname “Onii-sama”.
The series is a mega-hit, with a total of over 15 million copies sold, and after a TV anime adaptation in 2014 and a film adaptation in 2017, it was announced that the second season of the TV anime will be broadcast in 2020.

4位：Haruhi Suzumiya series

出典 : Amazon.co.jp

This is a Sekai-type school and youth story by Nagaru Tanikawa, published by Kadokawa Sneaker Library since 2003.
The illustrations are by NoIji Itou-sensei.
As of October 2019, 11 volumes have been published.

Depicting the various approaches to her “subconsciously embodying her desires” that take place behind the hilarious activities of the SOS group founded by the proud and eccentric high school girl Haruhi Suzumiya (Suzumiya Haruhi), this work is a smash hit, with the series selling over 20 million copies worldwide.
The number of copies sold per volume is the highest ever for a light novel, and the first issue of volumes 10 and 11 of “The Astonishment of Haruhi Suzumiya” sold over 500,000 copies.
The 2006 TV anime aired in 2006 was a mega-hit that made the history of the lanobe anime and late night anime, and the second season (Endless Eight) aired in 2009 was a big hit in a different way.

3位：Slayers!

出典 : Amazon.co.jp

Battle Fantasy by Hajime Kamisaka, published by Fujimi Fantasia Bunko since 1989.
It is illustrated by Rui Araizumi-sensei.
As of October 2019, 17 volumes of the main story plus a total of 30 volumes of the outer story plus 5 volumes of short stories have been published, and although the main story was once completed, it has resumed in 2018.

This light adventure follows the adventures and battles of Lina-Inverse, a beautiful, unassuming mage genius, and her friends.
It is the gold standard of comedic battle fantasy, which can be said to have set the tone for Japanese light novels, with a total circulation of over 20 million copies.
It was made into an anime for television five times between 1995 and 2009, and has also been made into a movie five times.

2位：Sword Art Online

出典 : Amazon.co.jp

Reki Kawahara-sensei has been publishing this battle fantasy based on a VRMMORPG from Dengeki Bunko since 2009.
It is illustrated by abec-sensei.
As of October 2019, 22 volumes of the main story and 6 volumes of the progressive version have been published.

Set in the near future, when VRMMORPGs have begun to spread, this story follows the struggles of the main character, Kirito, and his friends as they boldly take on VRMMORPGs, including Sword Art Online.
It has become a huge hit worldwide and the series has sold 22 million copies in total.
The anime adaptation of the series started in 2012, and the third season is being broadcasted as a large volume of the unprecedented 4 cool seasons.

1位：A Certain Magical Index (Index)

出典 : Amazon.co.jp

This science fantasy has been published by Kazuma Kamachi from Dengeki Bunko since 2004.
It is illustrated by Kiyotaka Haimura.
As of October 2019, 47 volumes of the book and 1 volume of short stories have been published.

Set in a world where supernatural abilities have been scientifically proven, this story depicts the conflict between the magic and science sides from the perspective of several characters, including Kamijou Touma.
In addition to the main story, the spin-off manga “Toaru Kagaku no Railgun” with Misaka Mikoto as the main character also became a huge hit, and the total sales of the series exceeded 31 million copies.

Naturally, media development was active, and the third season of “Railgun” was made into a movie, and the third season of “Railgun” was made into an anime.

Summary

These days, the total number of copies of a series that includes all the related books is announced rather than the sales of the novels alone, so if you rank only the novels, you’ll get a slightly different order.
However, the explosive sales of the comic book version is due to the fun of the original work, so the fact that the original work is great doesn’t change.
Without exception, the novels in this ranking are masterpieces of an era!