Niellefresne is a tall Elezen with gray hair and blue eyes who wears round glasses and a red vest.
Nielle cares deeply for F'lhaminn as the two were lovers. He worries about the well-being of Ul'dah and believes it needs to be reformed.
Nielle is seen as callous when showing no remorse for the death of Warburton, but deep down he cares and feels he must atone for what he's done.
Niellefresne was running the parade at Ul'dah, chastising Greinfarr for being late. Before they could leave he was stopped by F'lhaminn and told Greinfarr to take the flower as a precaution. As the parade began all seemed to be going well until a gobbue broke free and knocked over the carriage and injured F'lhaminn. Running to her aid to check on her, she woke up and alerted him of a rampaging gobbue. Thancred jumped in to distract the beast as the two ran to safety. After its defeat the gobbue went on another rampage while Nielle and F'lhaminn gave chase. The gobbue crashed into a wall, knocking Warburton into a coma. These events are later witnessed seen by the Warrior of Light in an echo flashback.
The Warrior of Light goes to the goldsmiths guild to sell one of the flowers from the parade. They were taken back in time and met Nielle who noticed that the flower does not wilt and paid them for compensation. In another echo he appears at the gladiator's guild speaking with Greinfarr about how Ul'dah is in need of a reformation.
In what appears to be the Platinum Mirage, Thancred plays a betting game for Nielle to admit the truth to everyone present. Thancred explains there are merchants in Ul'dah looking to profit off the war with Garlemald, and there are people looking for fame and glory in the people's time of need. Nielle doesn't admit to any of his claims and leaves.
Outside Ul'dah, Corguevais plans on taking Ascilla back to Ala Mhigo, but Nielle and the others disagree. He reveals Ul'dah is in danger soon from something worse than the empire. Uninterested in the girl, Nielle worries about the safety of Ul'dah. Corguevais blows the horn that caused the gobbue to go rampant in the parade, summoning a horde of coblyns. As he makes his escape Ascilla is left behind and is attacked by the creatures. F'lhaminn defends her, but is knocked unconscious. Nielle asks the Warrior of Light to help them fight, and after the battle, they take F'lhaminn back to Ul'dah.
The group discusses what Corguevais meant by the threat and assumes he was a Garlean spy. F'lhaminn wakes and tells the group to seek out Thancred who was investigating the Garleans. He was exiled for unknown reasons and Nielle promises to look into the matter himself.
Nielle plans on resurrecting Warburton for the information he had, as well as to atone for causing his death. As he is about to prepare the corpse he is shocked about what he finds in the coffin. A robed man comes behind him and stabs him in the back. Thancred and the Warrior of Light find him, and Nielle points to the girl Ascilla and shortly passes away.