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