Neuronist's appearance is that of a huge grey bloating corpse with tentacles, heavy makeup, and very long fingers with sharp inch-long nails with nail polish. Though its race is androgynous, Neuronist declared itself to be a Big sister. She wears a black leather outfit akin to a Dominatrix
Neuronist is in charge of torturing the prisoners and extracting information from them. She takes delight in her job and inflicting pain on others, especially since her favorite food is brains. She is very talkative, casually conversing with her victims whilst she prepares her tools. She is also quite vain; she considers herself more attractive than both Shalltear and Albedo.
The Undead King Arc
- Main article: The Undead King Arc
The Bloody Valkyrie Arc
- Main article: The Bloody Valkyrie Arc
Shalltear Bloodfallen inquires Solution Epsilon whether or not she got along well with Neuronist Painkill. The battle maid regretfully said that she cannot understand that interrogator’s aesthetic sense. Meanwhile, Albedo informs Ainz Ooal Gown that Neuronist is keeping close watch over the captured Sunlight Scripture members. The Overseer offers a suggestion to Ainz that they should summon Neuronist for guidance in the Frozen Prison, but the latter refuses considering that the interrogator talks too much. After all, this is over, Albedo initially plans to lecture Neuronist and caution her not to babble too much as he said until her master said otherwise not to do so.
The Invaders of the Large Tomb Arc
- Main article: The Invaders of the Large Tomb Arc
According to Demiurge, Neuronist Painkill was able to successfully reduce the authority of those in power from the Eight Fingers with the help of Mare and Kyouhukou. With the assistance of these three in their operation, they can now begin to slowly infiltrate their organization's ranks until the Re-Estize Kingdom comes under our full control.
While so, Neuronist was said to have assisted in Entoma Vasilissa Zeta's recovery from her fight with Evileye. When several worker groups invaded the tomb, all of Nazarick was put on high alert to test out its defenses against the invaders. Heavy Masher's group had set off a trap, at least one of its members was sent directly to Neuronist Painkill's torture chamber, where he was repeatedly tortured by her.
The Pleiades Day Arc
- Main article: The Pleiades Day Arc
Neuronist Painkill met CZ2128_Delta, Yuri Alpha, and Aura Bella Fiora in the 6th Floor. She explained that she was going to visit Gashokukochuuou, with the rest of the Five Worst for a house-warming. When she explained the purpose of her gift, a bottle of perfume for men, she offered to educate the young dark elf in being a 'lady'. Though due to her close proximity to Neuronist, she caused Aura to run back to her floor.
The Witch of the Falling Kingdom Arc
- Main article: The Witch of the Falling Kingdom Arc
During the Fall of the Re-Estize Kingdom, King Zanac Valleon Igana Ryle Vaiself's head was brought a sign of peace to Ainz by traitorous nobles of the Kingdom. Ainz in his silent fury ordered the nobles and soldiers along with their families to be tortured by Neuronist. It was his intention to ensure that they would be given a fate where they would live in agony and no mercy.
|NOTICE: The following section and subsequent subsections are considered NON-CANON to the Overlord Light Novels.|
Mass for the Dead Arc
- Main article: Mass for the Dead Arc
Neuronist was among the NPCs that were killed when the dungeon was transported to the New World and the Chaos Beasts invaded. Her resurrection was delayed due to it not being a priority. After Neuronist was finally revived, her superior Cocytus apologized to her for the wait. Neuronist was relocated to the 1st Floor as the 5th Floor was deemed unsecure. She struggled to resume her duties but found herself overshadowed by the achievements of the protagonist. The torturer she was feeling redundant as most of the information that she gained from her victims was already acquired by the protagonist. Due to this she began to hold a grudge against him, but after meeting him and speaking with him, found that the homunuclus in fact admired her work as a servant to Momonga. The Special Intelligence Officer later regained her sense of value when she prevented Nazarick from being exposed after she interrogated a captured knight who revealed that Marquis Pespea who was soon to arrive in the area. For her role in preventing such an exposure, she was granted a reward which she wished to plant a kiss on Momonga. However before she could do so, Albedo had her confined in the Frozen Prison under grounds that she was overstepping herself.
Neuronist later played a part in a competition among the female members of Nazarick to see who should be awarded the role of being the bathing attendant to Momonga. The torturer served as one of the judges in the competition, where the contestants had to clean the Brain Eater's body. The torturer relished the moment as a way to get back at Albedo but to her surprise found that the Overseer Guardian did an excellent job. With no grounds to disqualify her Neuronist admitted Albedo passed the trial. When Nazarick was doing a trial run of an idol show, Neuronist expressed her interest in participating and even offered the idols Acidity and Alkaline to use her "choir". However the producer Demiurge sadly informed her that the idol show would be a living showing and involve fighting against the Chaos Beasts in the ruined Throne Room. As fighting was required Neuronist was disappointed that she could not become one of the idols. The torturer though appeared at the handshake event after the idols performed before the Crack on the 6th Floor.
After the incident in Re-Blumrushur that saw the assassination of Marquis Blumrush, one of Demiurge's summons had captured the assassin. To determine who the third party was that was manipulating the corrupt noble, Neuronist was called to do an interrogation outside of Nazarick. However she was only able to learn that the assassin was hired by multiple intermediaries making the the identity of who put the hit on Blumrush a mystery. 
At the time of the "Nazarick Swimsuit Athletic Meet", Neuronist would be personally asked by Momonga to serve as part of his team in the "Mix Gender Water Cavalry" competition. Learning that she would be carrying Momonga, the torturer quickly accepted and would snub Albedo and Shalltear on her assigned role before the start of the game. Due to this the two women targeted Neuronist in a combined attack in the competition knocking her out of the cavalry unit.
For Nazarick’s formal Halloween Festival, Neuronist partook and volunteered to be a hostage for the witches attacking the dungeon in the defense training. Though she referred herself as a princess much to the chagrin of Albedo and Narberal who were the witches. The torturer was ‘saved’ by Cocytus and Entoma on the 5th Floor after the Flood Guardian caused a huge gust of wind to separate Neuronist from her captors.
- Neuronist Painkill is assisted by a group called the Torturers in her Area.
- Neuronist Painkill has a small torture tool based on the idea of Kidney Stones (which plagued her creator).
- According to Neuronist Painkill, the reason why all the NPC's are completely loyal to Momonga is that because out of the Forty-One Supreme Beings, he continues to stay with them until they were allowed to gain life.
- (To Heavy Masher's Member about his lower body): "My, to think it'd shrink this much. There's no need to be scared."
- (To Heavy Masher's Member): "One of the Forty-One Supreme Beings. He ruled over the other Supreme Beings in the past, and he is very, very cool. If you look at him once, you'll want to swear loyalty with all your heart, too. If Ainz-sama ever calls me over to his bed, I don’t mind offering my first time to him."
- (To Heavy Masher's Member about her master): "There was this one time Ainz-sama was staring at my body. It was the stare of a male selecting a target for his hunt. Then he turned his face away as if he was embarrassed. It made my chest tighten and sent chills down my back."
- (To Heavy Masher's Member): "That's right, a choir. Even fools like you that haven't sworn loyalty to Ainz-sama can dedicate their voices to sing his praises. The goal is a chorus. Ah, how electrifying! It's Neuronist's gospel music dedicated to Ainz-sama."
- (To Heavy Masher's Member about torturers): "It's no use~. It's not going to break from someone of your strength. They'll cast healing magic over and over, so you can get plenty of opportunity to practice."
- (To Heavy Masher's Member): "Listen well. Because he remained, we, who were created by the Forty-One Supreme Beings, were allowed to exist. Our very existence is to serve him. Do you think we'll show even a shred of mercy to some filthy thieves that tracked mud into the holy place where such an exalted being lives? Do you really think that?"
- (To Heavy Masher's Member): "My creator used to suffer from a little problem called 'kidney stones'. To pay respects to that, we'll start with this. Since it became so small, I don't think we'll have much problem putting it in."
- (To Heavy Masher's Member): "We're going to spend a long, long time together. You shouldn't start crying, because this is only the beginning."