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
Get all stars from Kinutanuki
Kinutanuki's Secret
Meet Kinutanuki
Amanozako's Secret
Get all stars from Amanozako
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
Ouni's Secret
Get all stars from Ouni
Use a hint in game
Meet Ouni
Get all stars from Ungaikyu
Ungaikyu's Secret
Neko's Magic
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
Meet Atakemaru
Get all stars from Kane
Kane's Secret
Meet Kanedama
Get all stars from Neko
Neko's Secret
Meet Neko
The Story
Yokai's Encounter