Muzan had called them all to a meeting, to speak with all of them about the demon he just found . They all listened intently, not missing a single word as he explained how he found you and that you couldn’t control your own demon art as it was too powerful for yourself to even contain. Sekido finally gettting the opportunity to speak, and asks Sekido “Muzan-sama, what is their demon art, if I may ask?” Muzan “Rewind. It’s an extraordinary ability. I plan to use it in the near future.”