Rosie

'Information found online is most likely outdated. All information is to be changed following theory debunk streams, upcoming Patreon comics, and the That's Entertainment.'

Rosie is an upcoming character with some affiliation with Alastor.

Alastor
Their relationship is similar to that of Jack and Mary's relationship from Mary Poppins Returns.

Trivia

 * Vivzie says Rosie and Alastor's relationship is similar to Mary and Jack's relationship from Mary Poppins Returns.
 * Vivziepop mentioned in her Vivzie Streem #9 live stream that she can't give information on Rosie because it's a heavy spoiler and also because she is an important character and is important to the plot.