The Edge of Fate is full of side quests, and Drifter's is certainly one of the most interesting. Continuing the thread of the Chess Puzzle in Episode: Heresy, Drifter's quest has you hunting Chess pieces around Kepler to try to piece together the history of the Aionians, and unravel the mysteries of the IX.
This is the shortest of the side quests in The Edge of Fate, and can be completed as soon as you unlock it. So, if you want to do it while completing the story, feel free to do so. Otherwise, you can leave it until afterwards as well, and it'll have no bearing on the rest of your experience for The Edge of Fate's campaign.
Correspondence
To begin the Correspondence quest, you'll need to head to the Curtilage Divide. Fast travel to the Exile's Accord and continue onwards.
In the middle of the platformed area, you'll find a Chess Piece lying on the floor. Interact with it to begin the quest.
1. Locate an Aionian Historian
Once you pick up the chess piece, Drifter will ask you to find an Aionian Historian, as he believes they have a relation to Aionian History.
Turn around from where you found the piece and walk up the ramp to find Malthas, the Aionian Historian.
2. Find the second Chess Piece
Malthas will tell you these chess pieces were used by the Aionians to send messages to Earth, before they became stranded on Kepler. They ask you to find more located around Kepler.
Your next Chess Piece to retrieve will be in the Curtilage Divide, not far from where you found the first. Head back towards where you found the first piece, and walk towards the opposite exit. You'll find the Chess Piece to your left, surrounded by Mattermorph vines.
3. Return the Chess Piece to Malthas
Head back to Malthas to give him the second chess piece.
4. Find Nine Chess Pieces across Kepler
Malthas would like you to retrieve more chess pieces from across Kepler. There will be Nine chess pieces for you to recover, all located within the Curtilage Divide. Head back to the area where you found the first chess piece; all Nine pieces will be located within this room.
For the first piece, head to the central pillar where the first piece was found, and walk to the other side of it. You'll find it laying on the floor.
The second piece can be found on the left wall, buried in Mattermorph vines.
For your third piece, turn around and walk forward; you'll find it underneath a House of Exile bunker.
To find the fourth piece, follow the wall around to underneath another House of Exile structure to find the piece atop Mattermorph vines.
From there, follow the path to the Right to find the fifth chess piece resting against a Mattermorph tree.
For the sixth piece, continue following the path around towards a shielded Generator, where you'll find the piece resting to the left of it.
Walk around to the opposite side of the shielded generator, where you'll find the seventh piece nearby a boulder.
From here, jump over onto a platform to your Left to find the eighth piece hidden within a Mattermorph pile.
For the Ninth and final piece, jump over to the opposite platform behind you, where you'll find the piece lying within Mattermorph vines.
5. Return to Dean Rebecca
Once all Nine pieces are collected, you'll have to safely transport them all to Dean Rebecca, who will be waiting in the Caldera.
Fast travel to the Caldera, and walk down the stairs to meet with Dean Rebecca and safely hand over the Chess Pieces. This will conclude the Correspondence quest.
