He is first encountered arguing with Rulindil in Elenwen's Solar during Diplomatic Immunity.
He can also be killed during "A Cornered Rat." If any of the patrons are asked for information regarding Esbern in the Ragged Flagon while Gissur is there, it will trigger an event where he then leaves the Ragged Flagon to meet with a Thalmor wizard accompanied by two Thalmor soldiers. He informs them that the Blades agent is in the Ragged Flagon asking about the old man.
The group of them then head to Ragged Flagon together. They will attack on sight, but if the Dragonborn manages to evade them, they will go into the tavern and ask where they might find the one asking about Esbern. The Flagon staff and Thieves Guild patrons refuse to cooperate, even after threats, and eventually the three Thalmor will leave. Gissur, however, remains behind and will from then on attack the Dragonborn on sight.
Interrogations and expensesEdit
Gissur: "But I need that money, I earned it! I have my own expenses, you know."
Rulindil: "Silence! Do not presume, Gissur. You are most useful, but do not presume. We have more informants who are less...offensive."
Gissur: "But no one else has brought you such valuable information, have they? [pause] Etienne, he's talked, hasn't he? He knows where that old man you're looking for is, he told me himself."
Rulindil: "You'll get your money when he's told the rest of his story, as agreed."
Gissur: "So he has talked! I knew it!"
Rulindil: "Everyone talks, in the end. Now, I have work to do. Leave me to it, if you ever want to see the rest of your payment."
Gissur: "Can I...I could help you. He'd talk to me. He trusts me."
Rulindil: "You'd like to come downstairs with me, is that it, Gissur? Shall we loose his bonds and put you in a cell together? You can ask him anything you like and see how he answers."
Gissur: "No, no. I...I'll wait outside."
Rulindil: "That would probably be best. [pause] Now get out!"
- (Talking to himself): Etienne most know the cause of the dragons returning who else would greasy thom? No they would see right through him.
- If an attempt to pickpocket him is made in the Ragged Flagon and he attacks, the guild members will attack him, no matter if the Dragonborn is part of the Thieves Guild or not.
- Gissur may be found outside the Ratway with the three Thalmor if he misses the Dragonborn and Esbern inside. He and the Thalmor will attack on sight.
- Using Fury or a higher level "frenzy" spell on Gissur will make all Thieves Guild members hostile to the player, even if hidden. However, attacking him on sight without casting Illusion spells at him results on no hostility from the Thieves guild.