Manga Volume 19 Kimetsu no Yaiba It has sold more than 1,378 million, during its first week, placing itself as the third manga in history to sell more than 1 million copies in a week.

the achievement of Kimetsu no Yaiba It only compares to great as Shingeki no Kyojin that manages to sell more than 1 million copies, for a week, on two occasions and one piece who is placed as the king with 45 occasions.
Kimetsu no Yaiba It is a manga written and illustrated by Kiyoharu Gotōge that began to be serialized on February 15, 2016 in the weekly magazine Weekly Shōnen Jump from the Shūeisha publishing house. Currently, the anime adaptation is available in Crunchyroll for Latin America.
Synopsis of Kimetsu no Yaiba:
From ancient times, rumors of demons of devours of men who were lurking in the forest abounded. Because of this, local people never venture out at night. The legend says that a demon killer also wanders at night, chasing these bloodthirsty demons. For the young Tanjiro, these rumors will soon become his harsh reality… Since the death of his father, Tanjiro has proposed to support his family. Although their lives can be hardened by tragedy, they have found happiness. But that ephemeral heat is destroyed one day when he finds his family killed, and the only survivor, his sister Nezuko, becomes a demon. To his surprise, Nezuko still shows signs of human emotion, and thought… Thus begins Tanjiro’s request to fight demons and make his sister human again.
(C)吾峠呼世晴/集英社・アニプレックス