Demon Slayer: Kimetsu no Yaiba has been the perfect example of how a well executed anime adaptation could bring more eyes to the original manga series, and this has been especially true in Japan. As much as it's been a hit around the world, there's been a notable increase of sales of the original manga run in Japan with many of its weekly sales numbers quickly approaching the king, One Piece. Sold out stock caused some panic, and the sales numbers are continuing to increase with each passing week. But now it's crossed a major milestone.
As noted by @KnYSource on Twitter, Demon Slayer is currently the best selling series of 2019, with 200,000 more sold than One Piece currently. But while this is a huge step forward, it's still far from completely surpassing One Piece's records.
Kimetsu no Yaiba is currently the best selling manga series of 2019, it's currently ahead of One Piece by 200k. pic.twitter.com/Qn8CvfvFk5— Kimetsu no Yaiba (@KnYSource) November 1, 2019
While Demon Slayer is outselling One Piece, no single volume of the series has approached the sales of the latest One Piece volume in Japan. As pointed out by @newworldartur, Volume 94 of the series has sold over 1.7 million copies in the first three weeks of October but these sales numbers are still impressive. The actual breakdown is much more promising, too.
Rather than any single volume of Demon Slayer outselling One Piece, these numbers are coming mainly from fans in Japan wanting to continue on the series beyond where the anime's first season ends. It's been a lot of fans buying multiple volumes of the series, and this has increased the overall volume of sales. So while Demon Slayer's latest volume isn't the top in terms of popularity, the manga itself sure is heading there!
The series is currently airing new episodes of the English dub on Adult Swim's Toonami programming block. If you wanted to check out the original Japanese run of the anime for yourself, Demon Slayer: Kimetsu no Yaiba's first season is now complete and streaming on Crunchyroll, FunimationNOW, and Hulu. Originally created by Koyoharu Gotoge, Demon Slayer: Kimetsu no Yaiba first debuted in Shueisha's Weekly Shonen Jump in February 2016.
VIZ Media fully licensed the series for an English language release, and they officially describe Demon Slayer: Kimetsu no Yaiba as such, "Since ancient times, rumors have abounded of man-eating demons lurking in the woods. Because of this, the local townsfolk never venture outside at night. Legend has it that a demon slayer also roams the night, hunting down these bloodthirsty demons. For young Tanjiro, these rumors will soon to become his harsh reality. Ever since the death of his father, Tanjiro has taken it upon himself to support his family. Although their lives may be hardened by tragedy, they've found happiness. But that ephemeral warmth is shattered one day when Tanjiro finds his family slaughtered and the lone survivor, his sister Nezuko, turned into a demon. To his surprise, however, Nezuko still shows signs of human emotion and thought… Thus begins Tanjiro's request to fight demons and turn his sister human again."