The Imperials and the Stormcloaks are in the middle of a massive civil war, a fact you’ll discover almost immediately upon starting Skyrim. Choosing a side can be a tough decision, but rest assured you’ll earn the same Achievements regardless of which faction you join. There’s also no real item advantage to either side, so don’t worry about missing out on some incredible sword or jewelry. As a matter of fact, the weapons and armor you receive as quest rewards are usually leveled, which means their stats scale to match whatever your current level is at the moment of collection.
That just leaves story as the determining factor. Are you the type who loves decimating rebel scum? Or do you prefer toppling your rulers because you think you know better? If you’re dying to see both outcomes, create a save file just before you make a decision, then load and try joining the other side.
Once you’ve joined either faction you’ll earn the “Taking Sides” Achievement/Trophy.
You can join up by visiting the headquarters in Windhelm, found in eastern edge of Skyrim. After you complete the “Joining the Stormcloaks” mission, you’ll have the opportunity to recite an oath to Galmar. Doing so cements your decision to join the Stormcloaks, so if you’re having second thoughts, now is your chance to back out.
You can join up by visiting the headquarters in Solitude, found in the northwest corner of Skyrim. After you complete the first quest labeled “Joining the Legion,” you’ll have the chance to recite the Imperial oath to Tullius. Doing so cements your decision to join the Imperials, so if you’re having second thoughts, now is your chance to back out.
The Bard’s College is just east of Solitude, which can be found in the northwestern corner of Skyrim. This is a minor faction, but well worth your time. After completing the first quest called “Tending the Flames,” you will receive upon completion of each subsequent quest an instant +1 to six of your skills. For example, after completing “Finn’s Lute,” Finn will give you +1 in Light Armor, Sneak, Pickpocket, Lockpicking, Alchemy, and Speech. There are two additional quests that cover the remaining skills.
The Blades can be found in Sky Haven Temple. Unfortunately, you cannot reach this location until after you complete the main story quest called “Alduin’s Wall.” Once you meet Delphine, you can bring any follower to her and she’ll “recruit” them. These recruits will still be your followers, but they will now live in Sky Haven Temple and be able to equip the powerful Blades armor and weapons.
If you bring three followers for recruiting into the Blades, Esbern will start marking on your map the locations of dragons, one at a time. Once you’ve killed the dragon, return to Esbern and he’ll mark another. If he won’t give up the next one, wait at least three days and try again.
The Greybeards reside in High Hrothgar, found on the tallest mountain in Skyrim. You’ll eventually get here if you follow the main questline of the game, but if you want to go early, look for the massive set of stairs leading up the mountain that start in Ivarstead.
Provided you’ve completed the main story quest called “The Horn of Jurgen Windcaller,” you can talk to Arngeir and ask him to mark a location on your map of a single undiscovered Word Wall. You can repeat this after each discovery until all the walls have been found. If he won’t give up the next one, wait at least three days then try again.