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
Get all stars from Kinutanuki
Kinutanuki's Secret
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
Get all stars from Kinoko
Kinoko's Secret
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
Use a hint in game
Meet Kudagitsune
Get all stars from Atake
Atake's Secret
Meet Atakemaru
Get all stars from Kane
Kane's Secret
Neko's Magic
Meet Kanedama
Neko's Secret
Get all stars from Neko
Meet Neko
The Story
Yokai's Encounter