This Trophy is story related and cannot be missed.
*** Spoiler - click to reveal *** The Barbarian King, Titan Minotaur, Mole Cerberus, Euryale, & Perseus. For the first 2 bosses you get items when you defeat them. Defeat him and this Trophy should appear.
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