To unlock the following Secret Trophies, complete the following tasks.

Trophy	How to unlock
Castle of the Worm (Bronze)	Complete Main Quest Chapter 3.
Chasing Shadows (Bronze)	Complete Main Quest Chapter 2.5.
Council of the Five Companions (Bronze)	Complete Main Quest Chapter 5.5.
Daughter of Giants (Bronze)	Complete Main Quest Chapter 2.
Soul Shriven in Coldharbour (Bronze)	Complete Main Quest Chapter 1.
The God of Schemes (Silver)	Complete Main Quest Chapter 6.
The Halls of Torment (Bronze)	Complete Main Quest Chapter 4.
The Harborage (Bronze)	Complete Main Quest Chapter 1.5.
The Shadow of Sancre Tor (Bronze)	Complete Main Quest Chapter 5.
The Tharn Speaks (Bronze)	Complete Main Quest Chapter 3.5.
The Valley of Blades (Bronze)	Complete Main Quest Chapter 4.5.