Repetitive Action

Is a technique practiced and taught by a few individuals from the Demon Slayer Corps. It is introduced by Genya Shinazugawa, who has learned it from Gyomei Himejima.

Overview
The technique allows the user to reach a state of Total Concentration by opening all five senses, which makes it similiar to the technique of the Breathing Styles. By repeating a set of pre-determined movements (like constantly praying and remembering a moment of intense anger and pain), the user can constantly raise their concentration and thus draw out all the physical powers of the body for a long period of time. The strengthening causes increased body temperature and a accelerated heart rate.

A Demon Slayer utilizing both Breathing Styles and Repetitive Action can gain immense strength that even rivals Upper Moons of the Twelve Kizuki. It is later revealed that using both techniques can help to unlock the Demon Slayer Mark and to maintain it for a prolonged time.

Known Users
Gyomei Himejima - Gyomei is constantly praying buddhist mantras by saying "Namu-Amidabutsu".

Genya Shinazugawa - Genya Shinazugawa cannot use Breathing Styles, thus he has to rely solely on the technique of Repetitve Actions to reach Total Concentration. Like his tutor Gyomei he does reach this state by repeating prayers. The Mantra that Genya repeats in order to reach/maintain this technique is the set of prayer of the Amida Sutra.

Tanjiro Kamado - Tanjrio learned this technique after consulting Genya. He raises his concentration to its maximum limits by remembering the faces of his loved ones and repeatingly recalling Kyojuro Rengoku's phrase "Keep your heart burning".

Inosuke Hashibira - Inosuke quickly understood the concept behind the Repetitive Actions by watching Tanjiro. He imagines the Tempura that he ate together with his training group and repeatingly calls out his favorite phrase "Pig Assault" as his mantra. To Zenitsu's suprise, Inosuke indeed gained enough strength to move a boulder.