The Thieve's Guild is a joinable faction in Skyrim. It comes very handy if you are a stealth player, a high sneaking skill is usefull.
Joining has the following Benefits:
- Good Armor sets
- Access to Chillrend, a very powerfull sword
- Tonilia, a fence selling Daedric weaponry
- Chests to train Lockpicking.
- Unlimited thievery radiant quests which reward gold
- Master-level training in Lockpicking, Archery, Pickpocket and Sneak
- Guards can be bribed
- The Skeleton Key, an unbreakable lockpick (temporary)
- The Disarm shout
The primary questline consists twelve quests, most of which are blackmailing and courier missions.