She came into the world as part of House Dvora; after the fall of the Imperator, she and her cousin were sent to live in House Ixion, where she was frightened by the housekeeper and mysterious whispers in the House.
Years later, she joined the Order of the Weal and was recruited to be Chatelaine Thessalia's mnemonic. The housekeeper called her "my little book". When the babel attacked the housekeeper on the frontier in time, it left the little book alive, hoping she would follow it to Earth so it could use her as an exit route after carrying out its plan. Indeed, the little book mercy-killed the housekeeper and immediately started plotting to defeat the babel. She was picked up by posthuman scavengers and bought a time-aware bio-suit that allowed her to travel through time.
After hearing rumours from Civitas Solis about ripples in time, Larissa used the suit to go to 17th century England. Faction Paradox's anti-Homeworlder loa stopped her from being able to speak any recognisable language, and Larissa killed everyone in her way before being subdued by physical effort. Since she appeared during an anti-Catholic craze, Corinthian Tom bought her and marketed her to the public as "the Jesuitess", sent by the Pope to assassinate the King. He presented her in the House of the Infernal in 1678.
Hearing that Faction Paradox had an interest in the Jesuitess, Doctor Bendo sent Aphra Behn to preemptively buy her from Corinthian Tom. However, Tom would only sell the Jesuitess' sleek black skinsuit, which Aphra decided to keep for herself. When Faction Paradox infiltrated the House and restored the Jesuitess' power of speech while trying to kidnap her, an angry anti-Catholic mob attacked the building. In the chaos, the Jesuitess escaped and began to search for her skinsuit. When Ratcatchers arrived to quiet the mob, Cousin Greenaway pretended to be the Jesuitess so she'd be brought into Bendo's base of operations, where she overpowered the guards with her whip and stole the egg.
The Jesuitess went to Aphra Behn's to reclaim her skinsuit, but Mother Sphinx and Doctor Bendo had traced her there, and Bendo shot the Jesuitess in the abdomen. Wounded, she erased him from time with the continuity needle and fled down Aphra's timeline, which her suit read upon tasting Aphra's blood; in the process, she regenerated into a new form.
A woman appeared in a house near young Aphra Behn's house. Eff thought she was a nymph and pledged herself to her, naming her Larissa. Larissa travelled through Aphra's life, looking for moments where she interacted with temporal anomalies. This led her to appear in the Salomon House to ungag Aphra and knock one of the Servicemen unconscious; Larissa and Aphra confronted Nick Plainsong, but before killing him, Larissa realised that though he was a temporal anomaly, he was not her target.
Many years later, Larissa guided Aphra through London to a church where Nick Plainsong was showing the Faction Paradox shrine to Jeova Unus Sanctus and Nate Silver. Seeing the babel within Jeova, Larissa attacked him, and the babel entered her. Furious, Aphra stabbed Jeova with the continuity needle, causing the ripples in time that Larissa originally followed; Aphra also destroyed Larissa's skinsuit to stop the babel from escaping. Finally, Cousin Greenaway and Erasmus together destroyed the babel and saved Larissa.