Far Cry Primal

This achievement is supposed to pop when you raise the population of the Wenja village to 20, it didn't pop for me until my population had hit 100. From talking to Ubisoft on the forums there were issues with day 1 achievements that caused some achievements to not pop for many people.

The population of your Wenja tribe is the total number of people living across all of your captured locations. You can start gathering members as soon as the free-roam map opens up, after helping Sayla very early in the story—at this point in the game, you will have two tribe members already (you and Sayla). This achievement should pop as soon as you recruit the 18th new member.

On your map, any activity that shows “Population” as one of its rewards when you hover over it will contribute to your population total. The amount for each activity varies and is possibly random. I seemed to get five new tribe members for capturing an easy-level outpost, three for claiming a bonfire and up to four for the completion of a Wenja Help: Escort mission (depending on how many I managed to keep alive during the mission). You will also be rewarded with Population for some story quests, meaning you should get this even if you're not actively doing side quests.

To check the current size of your tribe, press , navigate over to Tribe and then down to the bottom-right icon on that page of nine (it looks like shelter). This shows a filling meter of rewards based on population, with your current population number at the bottom. The first reward tier is at 20 people, so it should coincide with the achievement.

This achievement can be completed immediately after the map opens for free roam, even before you do the story quest to help Tensay. It was only my second achievement in the game, popping after about an hour and a half of playtime.