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