Some new information for Mysterious Book has been released, it should be added

[Casterway]

This article confirms the game has only six chapters: https://metro.co.uk/2026/04/22/yosh...eview-a-nintendo-animal-documentary-28067758/

Also these filenames reveal some creature names:

https://assets.nintendo.com/video/u...0T/06_creatures/casterway/casterway-video.mp4

https://assets.nintendo.com/video/u...dF0T/06_creatures/peckadee/peckadee-video.mp4