Who is the main villain?

Alduin the World-Eater is the dragon you must stop in the main quest.

Which factions can I join?

The Companions, College of Winterhold, Thieves Guild, Dark Brotherhood and Bards College.

What is the civil war?

A conflict between the Imperial Legion and the Stormcloaks that you can choose a side in.

Skyrim Main Quest, Factions and DLC Explained

Skyrim's story is big, but its best feature is that you choose when to follow it. This guide covers the main quest and factions at a high level. Spoilers ahead for the main quest.

Key takeaways

The main quest: you are the Dragonborn and must stop Alduin the World-Eater.
Factions: the Companions, College of Winterhold, Thieves Guild, Dark Brotherhood and Bards College.
The civil war pits the Imperial Legion against the Stormcloaks.
Three DLCs, Dawnguard, Hearthfire and Dragonborn, are included in the Special and Anniversary Editions.

The Elder Scrolls V: Skyrim – Official Trailer · YouTube

The main quest (spoilers)

You are the Last Dragonborn, in the province of Skyrim 201 years after Oblivion. The Greybeards and the Blades are key groups. Alduin is finally killed in Sovngarde, the Nord afterlife. You can ignore the main quest and come back whenever you like.

Factions

The Companions: a warrior guild.
College of Winterhold: a school of magic.
Thieves Guild: a criminal network.
Dark Brotherhood: an assassin guild.
Bards College: a school for performers.

The civil war

Skyrim is in a civil war between the Imperial Legion and the Stormcloaks. You can pick a side. Think about it before you decide, because it changes who controls parts of the map.

The three expansions

All three DLCs are included in the Special and Anniversary Editions.

Dawnguard: vampire hunters against Clan Volkihar, crossbows, and werewolf and vampire lord forms.
Hearthfire: build houses and adopt up to two children.
Dragonborn: the island of Solstheim, the villain Miraak and dragon riding.