It sounds as though players will be charged with building and managing a clan of survivors, who'll need to be trained up in order to repel attacks from the infected and rival clans.
Players will be able to craft weapons, mount hostage rescue missions and go on raids for medicines and antibiotics to combat outbreaks of malaria and dysentery.
A list of the Trophies available in The Last of Us was published online last week. It included a Bronze Trophy called 'Populace', which is earned by building a clan to 40 people in Factions.
According to the details on Pastebin, "Factions fight over territory, supplies, and lives to grow their size and influence. There is safety in numbers - each faction is trying to rebuild its population by finding supplies."
Official details about the game's multiplayer component have yet to be revealed, but Naughty Dog said last week that it's planning to release three The Last of Us DLC packs post-launch, including one single-player expansion and two multiplayer add-ons.