The Falinesti Faithful are a group dedicated to the protection and tending of the four sites that the Falinesti tree city travels between every season. Despite Falinesti having gone missing centuries ago they tend these sites in the hope that it will one day reappear. They have many theories as to why the city went missing, ranging from simply getting lost to having been stolen by a Daedric Prince. They object to the current efforts of the Aldmeri Dominion to excavate the sites for artifacts.
The Fighters Guild is a mercenary organization found all over Tamriel. To join, go to any Fighters Guild and speak with Aicessar, Basile, or Hilan (regardless of your alliance) and tell them you're ready to join. To gain reputation with them, you must destroy Dark Anchors or kill Daedra and undead. Good relations with the guild has many benefits, including new skills and abilities.
First Auridon Marines
The Firstmages are a group of mages residing within Aetherian Archive. They began to occupy the tower in the First Era. It was here that they found the Great Source, which granted the Firstmages long lives. When the Celestial Mage arrived during the Interregnum, her very presence destroyed the Great Source. Now, many of the Firstmages worship the Mage, whom they call the Learned One, on the upper floors of the Archive, which have been devastated by the Learned One's magic. The Learned One does not wish to be disturbed, and the Firstmages on the upper floors will defend her with their lives. The only Firstmages who value their lives over their magic are Firstmages Anirwen, Arnure and Earil, who reside on the first floor of the Aetherian Archive.
Fists of Thalmor
The Fists of Thalmor are a military arm of the Aldmeri Dominion's government. They enforce the decisions of the Thalmor, the Dominion's effective executive, and are not affiliated with the Dominion's normal army. Owing to their name, the Fists of Thalmor are sometimes confused with the Thalmor themselves. Some members of the Thalmor are unhappy with how that is affecting their perception by the public, and have proposed that the Fists be renamed to their previous name of Justiciars.
The Forebears are one of two major cultural factions in Hammerfell. They are in a constant struggle with the Crowns to be the dominant force in Redguard society. While the Crowns are the more traditional voice, the Forebears advocate peace with their former enemies and have no trouble trading with them.
The Frostbite Raiders are a raiding band based on an isle off the Frozen Coast in Western Skyrim. The group came to trouble when a Sea Giant, Chief Gruthar, led his Half-Giant kin to invade the island, killing many raiders—including their captain.
The Frostedge Bandits are a bandit gang found on Bleakrock Isle. They have been hired by the Daggerfall Covenant to terrify the locals and reawaken Daedric magic within Hozzin's Folly mine. They can be found at Hozzin's Folly and the Frostedge Camp.