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.
Yokai's Secret
Open the friend book(please install free DLC)
Get all colors back
Get all stars from Draculea
Draculea's Secret
Meet Draculea
Kinutanuki's Secret
Get all stars from Kinutanuki
Meet Kinutanuki
Get all stars from Amanozako
Amanozako's Secret
Meet Amanozako
Kawauso's Secret
Get all stars from Kawauso
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
Get all stars from Ouni
Ouni's Secret
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
Neko's Magic
Atake's Secret
Get all stars from Atake
Meet Atakemaru
Use a hint in game
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