Here is the full list of all 49 Yokai's Secret achievements. It takes around 1-2 hours to unlock all of the achievements on Windows.
Use a hint in game
Neko's Magic
Yokai's Secret
Get all colors back
Meet Draculea
Draculea's Secret
Get all stars from Draculea
Kinutanuki's Secret
Get all stars from Kinutanuki
Meet Kinutanuki
Amanozako's Secret
Get all stars from Amanozako
Meet Amanozako
Get all stars from Kawauso
Kawauso's Secret
Meet Kawauso
Get all stars from Akakami
Akakami's Secret
Meet Akakami
Kurage's Secret
Get all stars from Kurage
Meet Kuragenohinotama
Kinoko's Secret
Get all stars from Kinoko
Meet Kinoko
Ouni's Secret
Get all stars from Ouni
Meet Ouni
Get all stars from Ungaikyu
Ungaikyu's Secret
Meet Ungaikyu
Get all stars from Ichiko
Ichiko's Secret
Meet Ichiko
Kuda's Secret
Get all stars from Kudagitsune
Meet Kudagitsune
Get all stars from Atake
Atake's Secret
Meet Atakemaru
Open the friend book(please install free DLC)
Kane's Secret
Get all stars from Kane
Meet Kanedama
Neko's Secret
Get all stars from Neko
Meet Neko
The Story
Yokai's Encounter