This Trophy is story related and cannot be missed.
I've linked a video of all boss battles in TITAN mode for those having trouble at higher difficulties. Boss batch 1 is from 0:28:06 - 0:52:20
All credit goes to video's author for his work capturing and posting his extremely skillful playthrough. ProsafiaGaming https://www.youtube.com/channel/UC-2wnBgTMRwgwkAkHq4V2rg