Hashira's are teleported in a room, where there's a tv in the middle and a unknown letter on the floor

Sanemi: "What the fuck?!"

Gyomei: "Language, my child." Praying

Shinobu: "oh? What is this~?"

Giyu: "What kind of demon art is this.."

Muichiro: "mm.."

Rengoku: "Oh?! Where are we?"

Tengen: "FLAMBOYANT!!"

Mitsuri: "uhm.. w-where are we..?"

Obanai: gets into a fighting position