Here is the full list of all 18 Hollowed achievements.
Choosing Oco
Saving Inna
Ringing the Bells
Surviving the Collapse
Running from the past
Scaling the world
Seeing the future
Expressing aggression
Rejecting Life
Moving forward decisively
Creating a relationship
A life after death
Making a trade
Sinking deep
Meeting the god
Roaming the gods realm
Avoiding the seeking hands
Learning the motivation