Unexpected Fallen Children

What if Tanjiro and Nezuko are sent to a place in 1915 America? What happens when he finds that the underground isn't what he was told? Read to find out.
In my AU, Tanjiro is taught how to speak English but still reverts to Japanese because that's his native language. FYI, I will use translate for this, so please don't come at me for that I just don't know how to read, write and speak Japanese all that well. Also, Mettaton in my AU is Female because that's what the full body form looks like as well as his ghost form. I also do not own Demon Slayer or Undertale.