Fade to Silence

In order to get a Follower to the Expert level you have to have three talks with them.

I noticed these Follower talks happened more frequently when I had plenty of food and firewood in the camp, having a hut for each follower keeps the daily requirements down too.

You have to leave the camp and then come back later in order for the possibility of a talk. I kept teleporting to the Prairie, claiming a resource node, then heading back, and I was getting a chat pretty much every time I returned home.

The first two events will show a message that a followers trust in you has grown in the top left of the screen, and a beam of light will highlight them in the training grounds area behind the main tower. When you get near they will start talking, you then just wait till the message in the top left goes Green, highlighting the end of that chat.

For the final talk the message is slightly different in that I believe it says a follower wants to talk, but the beam and the place are the same. This talk will require interacting with the follower by pressing cn_A, the talk is then very similar to the recruitment chat. (I was always as supportive as I could be, not selecting any angry face answers).

Once this final talk is done a message will pop up on the screen informing you that the Follower is now an Expert in their three fields of expertise. This signifies that you have gained the full trust of that follower.

There are eight followers that can be recruited, four through events that trigger when you get near, these occur in The Flats, The Peaks, The Prairie and The Pit. The followers that are recruited through events are Vic (Kill a Stalker, find her, Kill 2 Stalkers, craft her a bow), Gani (Perform a ritual), Jin (Kill 3 stalkers while he puts out a fire) and Rhys (Cleanse Totem, then fight him till he weakens enough). Which area they appear in can change, and this also changes where the event is in that area.

The other four turn up at your camp, but I believe only one can turn up for each follower you have recruited through an event. That is to say your first drop-in will only occur after the first follower event, then you won't get a second until you find and complete the second event. I recruited all followers in one run as resources are eventually enough to keep everyone fed and heated, so I am unsure if the drop-ins still turn up if you don't recruit the event follower.

A follower you advanced to Expert in a previous run will still be Expert in a subsequent run, however you still have to have the three talks for some reason! Once all eight are Experts who fully trust you, the achievement will pop. (It took about 5 seconds, but popped the minute that the saving icon appeared).