This is a dual-sided trophy, paired up with:
The Hidden Trophy trophy in Vampyr worth 42 pointsContinue playing to unlock this hidden trophy
After you are employed by Pembroke, leave Swansea and Dorothy to continue down the side of the river canal to meet Clay. This serves as an introduction to the Embrace mechanic, which will give you experience for sacrificing the life of the chosen victim. Do be warned, as doing this will negate the following trophy:
The Hidden Trophy trophy in Vampyr worth 253 pointsContinue playing to unlock this hidden trophy
With the ability to save/control save data on the Playstation, perform the following:
1) Procure a spare USB drive that has enough room for, say, 5gb maximum.
2) Plug it into your PS4.
3) Go to Settings > Application Save Data Management > Saved Data in System Storage > Copy to USB Storage Device
4) Make a copy of your save data right as you have departed Swansea's company (you will be aware of the save state based on if the Y appears, as this is the autosave icon in the top right).
5) Load up your game, embrace Clay, wait for the trophy to pop, then return to the Save Data Management.
6) Instead of Saved Data in System Storage, choose Saved Data on USB Storage Device.
7) Overwrite your save with the older version that had been separated, then resume your game.