After joining the Thieves Guild, unnamed thieves in Riften and other various places, such as Riverwood, may attempt to steal items from one of the stalls, leading to their swift death at the hands of the guards. The Dragonborn can loot and kill them in full view of guards without fear of being arrested, despite the fact their loot is likely stolen. They are lightly armed and carry assorted gems and gold, but their armor cannot be looted.
Another type of thief can be found anywhere without joining the Thieves Guild. This type of thief will try to rob the Dragonborn with a dagger. One can choose to let him, scare him off, or fight him. If the Dragonborn is a member of the Thieves Guild they can tell the thief and he will walk away.
Another encounter that is possible after joining the Thieves Guild, is that a Thief NPC may run up to the Dragonborn in the wilds and state "Hail brother. I saw you there and thought you might need these," after which they will hand the Dragonborn items. This is only confirmed with both The Elder Scrolls V: Dawnguard and Hearthfire enabled while wearing a piece of Thieves Guild Armor (5 lockpicks were received).
- If the Dragonborn is wearing at least one piece from the Nightingale Armor set when approaching a thief, they may greet the Dragonborn and hand over "your cut" of what they have looted, typically in the form of money.
- Sometimes, if the Dragonborn walks into someone's house in Riften a thief will be inside. If the thief sees the Dragonborn, he will start running all around the house not saying a word. Killing this thief won't put a bounty on you.
- A Thief can also be seen being attacked by the guards around the marketplace in Riften. This could be the aftermath of the above situation.
- A Thief can also be seen leaving (with stolen goods - you can see miscellaneous items in his inventory when pickpocketed) or trying to pick the lock at the Riverwood Trader late at night.
- Interestingly, items in a thief's inventory are never marked as stolen.
- If a thief is stopped in Riften during the night then Talen-Jei may be seen the next day wearing an alternate form of his clothing that depicts a dragon on the back of it.
- When the player is a Nightingale and a female thief engages conversation with you, she will say "This job has made me a very rich woman.", then hand over "your" cut. But, the subtitles will still refer to the thief as a male. ( "This job has made me a very rich man.")
- Alright, hand over your valuables, or I'll gut you like a fish! (When encountered)
- Of course! I remember seeing you at the Flagon, my mistake. (When the player says they are also part of the Guild)
- Of course! I remember seeing you at the Flagon, my mistake. Good luck out there! (Variation of the line above)
- Yes, you look like you're very lousy with gold. (On failed persuasion)
- Nice try, but you don't scare me. I'm not going to ask again. (failed intimidation)
- Don't you walk away from me! (if the player says "I don't have time for this" or if the player backs out of the conversation)
- Multiple thieves may spawn in one location.
- If you take everything a Thief has by selecting "take all," then the Thief's clothes may be taken, but no clothes go into the Dragonborn's inventory.