Pillars of Eternity 2: Deadfire - Ultimate Edition

This achievement can be earned during the Beast Of Winter dlc and is for completing the 3 optional objectives of the main mission towards the end of this dlc.

You should get an invite quite early on to travel to Harbinger's Watch for the mission "Honored Guest" which is in the SE corner of the map. Just follow along with the main mission until you get the mission update "Death's Depthless Dominion" Then get the fragments and speak to Rynhaedr.

POSSIBLE GLITCH WARNING
Make a hard save here as you need to complete each of the 3 echo realms before jumping down the hole. I highly suggest doing the Drowned Kingdom on the west side of the map first, because there is a well known glitch which also happened to me on Xbox, so i assume it is highly likely the issue could be here also, in which one of the 4 soul fragments are either missing or you cannot interact with it. (For me it was the one under the southern Sunken Crown exit, which should spawn after interacting with the device above it). Others have reported not being able to interact with the soul on the device above.

Reloading prior to entering this area appears to be the only fix.

It popped for me straight away after finishing the 3rd objective area on Xbox, but others have reported that it pops at the end of this dlc.

Hope this helps someone, Cheers.

From Pink Freud PhD in the Xbox guide:
Just an FYI to anyone confused like I was, this achievement does not unlock right away when you get the in-game unlock. It *actually* unlocks, for whatever reason, at the end of the Beast of Winter DLC.

So don't worry if you haven't gotten it yet, just go play BoW.