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
Draculea's Secret
Get all stars from Draculea
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
Akakami's Secret
Get all stars from Akakami
Meet Akakami
Get all stars from Kurage
Kurage's Secret
Meet Kuragenohinotama
Kinoko's Secret
Get all stars from Kinoko
Meet Kinoko
Get all stars from Ouni
Ouni's Secret
Meet Ouni
Ungaikyu's Secret
Get all stars from Ungaikyu
Meet Ungaikyu
Ichiko's Secret
Get all stars from Ichiko
Meet Ichiko
Get all stars from Kudagitsune
Kuda's Secret
Meet Kudagitsune
Atake's Secret
Get all stars from Atake
Use a hint in game
Neko's Magic
Meet Atakemaru
Get all stars from Kane
Kane's Secret
Meet Kanedama
Neko's Secret
Get all stars from Neko
Meet Neko
The Story
Yokai's Encounter