"It doesn't matter what timeline I'm in, I'll be a hero that will save people as much as I can!" Ubuyashiki (Y/n), the great-granddaughter of Ubuyashiki Kiriya with a demon quirk got sent back in time by a time villain, to when demons still exist. How will she get back? What will she do about the man-eating monsters that are roaming around Japan now? ✨ A Kimetsu no yaiba x BNHA reader insert ✨ Will contain spoilers for the manga, so read at your own risk ✨(VERY) Slow updates ✨ Multiple endings at the end ✨ Most of the GIF's are not mine, except for the GIF's that are used for borders Also available at: Quotev and AO3 Hope you enjoy reading!