Nerissa was said to be a princess of the Seelie Court.
She first met Andrew while he was still a student at the Shadowhunter Academy, during a rescue mission the second years conducted. When Andrew saw her, he immediately pledged himself to her and decided to stay in the Faerie. They quickly fell in love and even had two half-Shadowhunter, half-faerie children: Helen and Mark.
During their time together, Nerissa gave Andrew a silver chain as a token of her love—a choker that the Shadowhunters would later say was enchanted to make Andrew fall in love with Nerissa—and she taught him the ways of the Fair Folk.
At one point, one of Nerissa's sisters laid claim to Andrew's brother, Arthur, using him as a plaything and torturing him. Nerissa kept it a secret from Andrew as long as she could. The couple remained together for seven years (which lasted only one day in the mortal world) until Andrew finally found out the truth about what was happening to Arthur.
Nerissa realized that he would feel guilty about it, despite him having no control over it, so she made new memories for him—false memories that would make it seem as if he was there against his will, that it would have been impossible to do anything to help Arthur.
Nerissa then set up their escape by releasing Arthur, who then attacked her to rescue Andrew, and Nerissa let them believe that she had been killed. Rumors spread that they merely had an affair, but official records based on Andrew and Arthur's statements say Nerissa enchanted and enslaved Andrew.
At first, Nerissa tried to care for their children, Helen and Mark, but found herself missing Andrew too much. Feeling that they were not enough to compensate for his absence, Nerissa had the children sent to Andrew. With nothing left to live for—and as a fey with the ability to choose her death—Nerissa died.
- The Red Scrolls of Magic (mentioned only)
- City of Heavenly Fire (first mention)
- Pale Kings and Princes (first mention by name)
- Lady Midnight (mentioned only)
- Lord of Shadows (mentioned only)
- Queen of Air and Darkness (mentioned only)