Here is the full list of all 16 Yissa Deep Realms achievements.
Start your journey
Clear First Realm
Clear Second Realm
Clear Third Realm
Clear Fourth Realm
Clear Fifth Realm
Clear Sixth Realm
Clear Seventh Realm
Clear Eight Realm
Clear Ninth Realm
Feed all souls
Release all souls
Gain access to the Hard Mode
Collect the majority of Red souls during one cycle
Obtain all upgrades
Beat the game on Hard Mode