Eleanor Nightingale is the psych-ops of The Hex, and Arthur's older twin sister. She sells Arcane Enhancements and Coda weaponry. Albrecht Entrati's experiments turned Eleanor into a Protoframe, a partial Warframe that still retains their humanity. Eleanor possesses Nyx traits. Originally a Britannic woman, Eleanor shared an idyllic childhood with Arthur, never fighting once. Eleanor would often braid Arthur's hair and use makeup on him. Eleanor and Arthur's grandmother, Callista Penrose Nightingale, came to live with them due to "Pelham's Syndrome", which caused her mental state to deteriorate over time, to the point where she would be "shrieking" for long periods of time, even for the duration of their school day. Their father would make mention of putting a pillow over her head, leading Eleanor to suspect that he actually did kill their grandmother when she suddenly stopped shrieking in the middle of the night. Prior to coming to Höllvania, Eleanor worked as a journalist. Despite her profession's habit of inflating stories for profit, she wanted to do some good with her work. After Arthur arrived in Höllvania and informed Eleanor of the events in the city, she felt a strong need to report on the Techrot infestation and inform the world of what had happened. She contacted a man named Danny MacIlvoy, obtained a forged visa and passport, and came into the city illegally. Due to the chaos within the city, she was able to slip in without incident. Eventually, she snuck into the subways, where she found an example of the Infestation - which she dubbed "Techrot" in her article on it. This would eventually replace the original name of the infection (Testudo Syndrome) and its scientific name (Technocyte Virus). Eventually, she became infected by the Techrot and sought a cure from Dr. Entrati. Before the events of 1999, the first volunteers that came forward to Dr. Entrati's offer to receive more than healing.

Nefarith is the leader of the Bonekrushers, a Landbreaker Clan that gained prominence by utilizing a strange gaseous material known as hazefyre. This substance, related to the Blight, temporarily enhances physical strength while inducing hallucinogenic and neurotoxic effects. The Endfield Intelligence Office has designated Nefarith as significant threat and predicts she will launch a major attack on the Civilization Band within the near future. She took control of the Bonekrushers and broke old clan rules to make them a powerful and terrifying force on Talos-II. Her main goal is to attack and destroy the civilized regions. Her clan uses a strange gas called hazefyre. It makes people stronger, but it also causes dangerous hallucinations. She can control the Blight, a dangerous decaying force in the world. She can manipulate the Aggeloi, which no one else in history has ever done.

Kokoro Momoiro was a victim of severe merciless bullying at her last school, and has resolved to never be a victim again. Upon arriving at Akademi, she immediately sought out the "bullies" of the school and desperately tried to get into their good graces for the purpose of making them see her as an ally, and not as a potential target. The firsthand knowledge of what it feels like to be bullied is still fresh in her mind, and she has absolutely no desire to abuse others, but she does it anyway...because she knows that she has to keep up the facade of being a bully in order to avoid being targeted by Musume and her friends. She has become what she hates, which has caused her to loathe herself deeply, but she would still rather hate herself than return to being harmed by others.

Hoshiko Mizudori is different from the other members of the bullies. She has no excuse for her behavior, such as receiving a poor upraising, having an inferiority complex, or being a former victim. She is simply a cruel person. The one and only thing that she cares about is her own personal gratification. Nothing else matters to her, especially not the thoughts and feelings of other people. She doesn't use any form of rationalization to convince herself that she is justified in harming others; the pure enjoyment she gets from doing so is reason enough.

The leader of the Bullies is named Mutsumi Rokuda. She is the daughter of a well-known loan shark, which has earned her the nickname "Musume Ronshaku," which translates to "Daughter Loanshark." Her rich father spoiled her rotten, and as a result, Musume grew up without any reason to treat others with kindness or respect. Gradually, she developed the belief that most people are "beneath" her, and that the "lowest" people are mere playthings for her to torment. Like a child who never learned the difference between right and wrong, she simply lacks the ability to see her victims as people who deserve empathy or compassion. She doesn't deliberately seek out victims, but when she spots one, she will happily seize the opportunity to treat another person like dirt.

Candice Catnipp is a Quincy and a member of the Wandenreich's Sternritter with the designation T: The Thunderbolt. Candice has a very short temper, as shown when she got annoyed at Bambietta for her habit of killing attractive male soldiers when irritated and then proceeded to get angry at Giselle for teasing her about her supposed tendency of having "fun" with her subordinates. She cares a great deal for her appearance, going as far as to get up hours before everyone else to do her hair, and cannot stand having it ruined in battle. Candice is also very shortsighted, reckless, and impatient; this volatile nature coupled with her horrible judgement of the situation causes her to make foolhardy decisions when engaging stronger opponents.

The vandal was none other than Ui's best friend. This was a massive shock to Ui, who had not detected even the slightest clue that her closest companion was connected to the vandalism. She also hadn't realized that one of the girls in her class was being bullied, or noticed that all of the victims of the vandalism actually did have something in common with one another. In retrospect, she felt that the vandal's identity should have been obvious to her from the beginning. This incident affected Ui dramatically. She couldn't help but wonder if she could have prevented the entire incident by simply being more observant. If only she had paid closer attention to her best friend, she would have realized what was going on, and would have intervened before the situation had a chance to escalate so drastically. She felt an overwhelming sense of guilt, almost as if the entire situation had been her fault. From that day onward, Ui swore to never allow a similar incident escape her notice. She became an extremely vigilant young woman, constantly on the lookout for potential warning signs that a hidden crisis was secretly underway. This earned her a reputation as a nosy girl who is utterly incapable of minding her own business - some students have even begun to refer to her by the mocking nickname of "Witness-chan."

Pippi Osu is part of Gaming Club at Akademi Academy. She is obsessed with rhythm games and gacha games, Pippi Osu is also best friend with Mai Wakahara with her anime ideas, and they make a perfect gaming duo. Pippi Osu spend money of gacha games to get more and more characters, calling her "whale". But even she can't resist of... some of characters, Pippi Osu won't resist to buy it or farming it, even Pippin Osu asked Mai Wakahara to make cosplay of specific characters.

Ichiko Saikou is the firstborn daughter of Saisho Saikou, the founder of Saikou Corp. She was first in line to inherit Saikou Corp from her father, although it would ultimately be her brother who inherited the company. As the daughter of one of the most intelligent and influential men of the 20th century, many people expected her to excel academically. However, throughout her teenage years, her performance at school was never above average. Because she failed to live up to the impossibly high expectations placed on her, she was treated unkindly by her peers, leading her to have many unpleasant experiences throughout high school. Ichiko Saikou vanished from the public eye in 1990. The disappearance of Ichiko Saikou is a mystery; nobody knows why she vanished or where she went. Some people theorize that she may have been unable to handle the immense expectations placed on her by her father and the world, so she fled Japan to live in secrecy overseas, where she enjoys a quiet and peaceful life. Other, more extreme theories postulate that her father executed her for failing to live up to his standards. To this day, nobody knows the ultimate fate of Ichiko Saikou or where on Earth she might be.

Nemesis is a character who attempts to hunt and eliminate you. Depending on what difficulty you have chosen, Nemesis might be invincible, and might also be disguised as one of the female students. She another assassin who wants to remove her competition? Or, true to her namesake - the Greek goddess of retribution - is she here to take revenge on you for the sins of her past? She is much more dangerous when she sees you.

Sister Marie Leroux is a Protoframe possessing Wisp traits. A member of the Devil's Triad alongside Lyon and Roathe, Marie is a nun that worships Sol, and was tasked by Albrecht Entrati to monitor the devil Roathe. She can be encountered in La Cathédrale after completion of The Old Peace quest. Marie sells Tektolyst Artifacts, as well as Antique Mods and Arcane Enhancements, and resources obtained from The Descendia and The Perita Rebellion. Marie Leroux was originally born to an affluent and influential family in Gaule, though with malformed feet, rendering her unable to walk. With her parents' efforts not remedying the situation, and to keep up appearances, Marie's mother took her to Cité de la Lumière and abandoned her there, still at a young age. Marie then turned to live with the other orphaned children in the city, where she would use her disability to her advantage to make money as a beggar. After some time, one of the Sisters of Sol found Marie and offered to take her in at La Cathédrale, which she accepted. At the cathedral, Marie would be educated and become a nun herself. Even in her new position, she would donate what she could to the children, who would eventually find their own way through life when they survived their circumstances. It was in La Cathédrale that Marie met Lyon Allard, and quickly became his close friend for how they understood each other. When Albrecht Entrati traveled to Marie's time and became "Cardinal Dimanche", Marie felt blessed to hear his passionate sermons, and was taken by his treatment of her, which subconsciously reminded her of the father that abandoned her. These feelings became a passionate belief in Entrati, and blinded Marie to the full picture of his character. Entrati would later reveal the truth to Marie and Lyon, give them Protoframe serums, and leave Roathe — who had just become a Protoframe himself and lost many of his memories — in their care.

General Elysion doesn't take any mercy for her enemies and for her weaklings squads. Elysion leads the most elite group called "The Iron Talons" and she doesn't like any weaknesses. Her left metallic arm enough to break the walls with it, and her revolver called "Punishment" with the most deadliest toxin bullets enough to melt her enemies. Elysion also hates anything that is related to romance and she has no interested in relationship. Elysion is also the most calculated and her status speaks for herself. "Your failure will not go unpunished"

Meninas McAllon is a Quincy and a member of the Wandenreich's Sternritter with the designation P: The Power. Like other Sternritter members, Meninas is loyal to Yhwach and is willing to attack Ichigo Kurosaki to prevent him from reaching her leader and interfering with his plans. She finds PePe Waccabrada to be a disgusting man. She holds a great deal of pride as a warrior, as she felt insulted when Rukia Kuchiki turned her back to go help her brother, but did not hesitate to strike her from behind. She can also be rather innocent and blissfully ignorant, as shown when she bid farewell to an unconscious Rukia, only to quickly realize that she couldn't hear her. Meninas has also shown a sense of camaraderie with her fellow Sternritters, especially to the four she is close friends with. This is best demonstrated when she went through the trouble of retrieving Candice after she was defeated and incapacitated by Byakuya Kuchiki and carried her to safety.

Sweeper is a red-haired, dual-dagger-wielding boss. She is a red-haired woman who faces the character Daffodill during the events of the "Fogden Game" episode inside a hidden Anomalous Realm located in The Scarlet's Den in Hethereau. She is portrayed as somewhat selfish and ambiguously evil. However, after being defeated by Daffodill, she shows a more perceptive side, questioning Daffodill's motives regarding Scarlet Letter and Madam T, and accurately calling out when Daffodill is putting up a front. She utilizes fast-paced dual daggers, relying on heavy dashes and agile slashes during combat encounters.

Suzie is extremely lazy, she prefers to sit on bed or couch, when she sees you she will extremely pout at you. Despite her laziness she can be too much sometimes, causing scenes, being dramatic queen. Especially at the school, when her grades drops. She doesn't want take walks, she doesn't want to do anything, she only wants to go home and watch Anime and she stays on social media.

The Sui siblings (and related concepts like artificial Feranmut hearts) connect to Arknights: Endfield through the legacy of Terra's gods and advanced technology brought over to the moon Talos-II. Evidence and theories within the community suggest that a potential 13th Sui sibling or Yanese Tianshi delegations traveled through the Cosmic Gate to Talos-II during the initial colonization phase, bridging the deep-dive mythological lore of Yan with the new frontier of Talos-II. These constructs and remnants on Talos-II are often repurposed by pioneers and local factions to tackle modern planetary threats like the Blight, acting as massive anchors or energy sources. For a deeper breakdown of how ancient Terran entities and Feranmuts influence the frontier of Talos-II.

Laevatain is a Rhodes Island Operator assigned to Endfield Industries where she serves as a specialist operator following the framework agreement between the two companies. With Warfarin's authorization, Laevatain once spent years in the north to carry out a solo field mission, thanks to her strong skills in independent operations. What's even more impressive is her exceptional performance in Endfield's tests on teamwork adaptability and communication skills. This is also reflected in her peer feedback. Most Endfielders who have worked with Laevatain give her high praise. They say she might come across as a "fiery girl" at first, but she's actually not fiery at all. Instead, she is an excellent listener and coordinator. However, she sometimes talks about things nobody really understands, like "the threat of demons". Most people assume she's referring to the Aggeloi, while others just have no idea what she really means. She spends a lot of time in freezing environments and has a surprising fondness for ice cream. "Hmm... This box of ice cream would melt by the time they reach Warfarin. I'll just eat them myself." She deliberately chose the name Laevatain (the name of Surtr's iconic giant sword) to distance herself from the "other" Surtr. She struggles with a constant fear of being consumed by her past, actively trying to live for her own future rather than obsessing over a life she didn't technically lead. Because the original Surtr suffered from severe amnesia, the data pulled from the Originium network was fundamentally broken. Laevatain woke up on Talos-II with no clear memory of Surtr’s life at Rhodes Island, but rather traumatic, confusing flashbacks of ancient Kazdel.

Yvonne is an operator in the Specialist Tech Division of Endfield Industries, currently responsible for research on Æther, Blight and related devices. At first glance, Yvonne looks like your typical rebellious fashionista — painting her horns, tail, and nails in eye-popping colors. She'll skip out on academic conferences just to snag the latest fashion magazines and pop albums. Drawn to all things new and unconventional, Yvonne has a knack for staying one step ahead of the trends, always marching to the beat of her own drum. But no one can deny that she is a true genius. Even back in her school days, she was racking up accolades in scientific research that others could only dream of. Everyone expected her to join a top-tier research institute and lead the charge in her field. Instead, Yvonne turned her back on it all and chose to join Endfield. The reason? She never explained it. Maybe you can ask her yourself. Yvonne strongly defies conventions. Instead of acting like a stereotypical academic, she treats her personal style with extreme care—dyeing her Vouivre horns, tail, and nails in bright, flamboyant colors. She has even been known to skip academic conferences just to buy fashion magazines and music albums. Despite her eccentricities, no one doubts her genius. Before even graduating college, she achieved massive breakthroughs in her field. She was brought into Endfield Industries via a specialized talent recruitment channel and leads critical research projects regarding Æther, Blight, and specialized automata. She prefers to build and tinker with her own unique inventions rather than using standard equipment, which includes modifying her own weapons into "Yvonne-specials."

Aemeath's existence is a closed predestination paradox tied directly to the Voidspace—a realm where time and space are completely distorted. Her timeline functions as a continuous, heartbreaking loop. She is a Frostlands native from the Roya Tribe who was once a Synchronist at Startorch Academy. She became the Exostrider's Resonator after overclocking in order to resonate with it, causing her to lose her body. She now roams throughout Lahai-Roi as a digital ghost invisible to everyone around her except for Rover, whom she met with during her childhood. Ten years before the present story, a massive Void Storm threatened Lahai-Roi. To protect her people, Aemeath forcefully overclocked her Forte to resonate with a massive mechanical Exostrider. Her human body disintegrated from the strain, but her consciousness survived as a virtual, digital entity invisible to almost everyone. She is a Frostlands native from the Roya Tribe who was once a Synchronist at Startorch Academy. She became the Exostrider's Resonator after overclocking in order to resonate with it, causing her to lose her body. She now roams throughout Lahai-Roi as a digital ghost invisible to everyone around her except for Rover, whom she met with during her childhood. Aemeath's absolute favorite hobby is playing video games, a passion that started back during her school days. She was given a stack of game cartridges as an apology after getting scolded by a teacher. The games completely captivated her, and her favorite title of all is the fictional Space Fantasy: Katya series, where she loves role-playing as the unflappable, space-faring hero saving the universe.

Nihilux is the ex-President of Furbobo Weekly, a gossip magazine. She is a comic artist and the author of Fluffy Across the Blue. Her pen name is "Blurry_QR_Colt," and she also has a sub account known as "HD_Bar_Colt" on Furbobocom. In reality, Nihilux's true Identity is one of Aha's human forms. Throughout the story, Nihilux tracks the Trailblazer's journey, dropping hints about her deep connection to The Elation (even claiming she was once a Mourning Actor). She openly opposes the IPC and pushes a philosophy that the joy of a journey matters entirely more than its destination. "To Roll the Stars in Astropolis". In a dramatic cinematic cutscene, Nihilux reveals her true self as the Aeon Aha, turning her entire mortal life into a massive, elaborate prank designed to entertain themselves and the Nameless.