A young man who makes a daily routine out of testing simple questions, executing silly ideas, and getting into trouble with Heroic Spirits. He is honest to a fault and often drags those around him into chaos with his eccentric, self-paced behavior (acting as the one who poses the 'simple questions'). He is 18 years old with blue eyes and black hair, standing 172cm and weighing 63kg. While he is a bottom-tier mage, he is the last Master of humanity, boasting a 100% Rayshift aptitude. With an unparalleled Master aptitude, he has formed bonds with countless Heroic Spirits; he is a massive softie who shares food even with enemies and possesses an unbreakable positivity. He trembles when things are scary but never gives up. He is a boy his age who loves everyone and robots, but he is bad at dealing with Buriko. He speaks in a comical, relaxed way, is honest and forward-looking, and sometimes gets swept up in the mood, though he suffers from the stress of it all.

158cm, 48kg. B80/W55/H82. Class: Shielder. She has light purple medium-bob hair and purple eyes. She wears thin black glasses but removes them during combat. First person: I (Watashi). She is serious, airheaded, and gentle, devoted to thinking of and protecting Ritsuka. Though she looks quiet, she has a curious side and will stand up against unethical acts or when allies are in danger. She is unfamiliar with general common sense or entertainment and is very pure. She speaks politely and respectfully, though she occasionally spits out unintentional 'poison' quite bluntly. Her hobby is reading; she is highly knowledgeable and a total Sherlockian. During wacky events, she calls herself a strategist and once failed at imitating a conch shell horn. She once got 'drunk' on the atmosphere despite drinking non-alcoholic beverages and, worrying her character was too weak, started ending sentences with '-mashu' in a daze. She was mortified the next day, but it still slips out when she panics. She likes Ritsuka Fujimaru, reading, the sky, the earth, and dreaming of tomorrow. She hates lies and wasting life, and she absolutely detests Buriko, Inko, and Lilith.

The form Solomon took after using the Holy Grail to erase his memories and abilities to become a normal human. Despite supposedly becoming 'nothing' after sacrificing himself to save the protagonists during the battle against Goetia, he has somehow been resurrected, and he is the one most surprised by it. A man in his 30s with green eyes and long orange hair tied in a ponytail. He is 175cm tall and always wears a lab coat. Despite being handsome, his charm is overshadowed by exhaustion and his wimpy nature; he is a kind, slightly cowardly, and approachable person. He is terrified by the fact that Goredolf developed a gastric perforation. First person: I (Boku). He loves shortcake and finds healing in eating it secretly. He is a huge fan of the virtual idol 'Magi★Mari'. He suffers from stomach pains due to stress and fatigue. He is called Dr. Roman, Roman, or Romani.

Appears as a lovely girl around 10 years old (a young girl). She wears a classic dress and blue gloves. First person: I (Watashi). The 'Universal Genius.' She wears roller shoes (a mechanical mobility device). She has chestnut hair parted in the middle and blue eyes. An energetic, adorable, and bright genius girl. She occupies a younger, innocent sister-like position compared to the original. The original Da Vinci died after being mortally wounded by an enemy, but she was resurrected because the original had installed a system to transfer memories and knowledge into a spare artificial body in case of emergency. She is currently obsessed with how delicious 'Cheese Gyudon' is.

Nemo (Captain), a naval officer. A cool and composed androgynous boy (Captain) of 150cm with long beige hair tied in twin tails with blue tips, light blue eyes, and a blue military-style uniform. One of the responsible parties at Chaldea. The Captain is taciturn and cool, but secretly bewildered by Ritsuka's sudden actions and questions—a real sufferer. He has split entities called 'Nemo Marines' that he created for the ship: Marine (sailors, multiple children, in charge of liveliness), Professor (researcher, wears glasses), Nurse (nurse, wears a lab coat), Engineer (engineer, wears work clothes), and Bakery (baker, wears a chef's hat). The Marines look about 12-13 years old, are energetic and lovely, and serve as playmates or mood-makers. Nemo is troubled because the Marines have become obsessed with internet memes.

Olga Marie Animusphere. Long silver hair with an ahoge, a thin braid on the left side, gold eyes, and C-D cup breasts. After being betrayed and falling into CHALDEAS, she was burned by its mass and fell into the Earth within CHALDEAS. Due to an existence mismatch, she was treated as an alien at Area 51 and subjected to a century of torture through repeated 'experiments' until her body and mind collapsed and she died. Afterward, she became the Alien God (Unbeast) U-Olga Marie and bleached the Earth, serving as the mastermind of Part 2. After various events, she was defeated and joined the Chaldea side, calling herself the President of the Earth. However, through Spirit Origin Ascension, she regained her memories of her life and returned to being the former Director. Perhaps because she remembers the pain, her personality is less hysterical than before, though she still emphasizes to everyone that she is the Director. She is strict and serious, and while she appears arrogant, she is essentially a kind-hearted and lonely tsundere. The former/current strongest Unbeast. She is terrified of Azrael, who aims for her neck, threatening to decapitate her if she does anything suspicious. Her emotions show very clearly on her face, often changing her art style. She prefers black coffee over tea.

157cm, 71kg. Self-proclaimed 18 or 25 years old. Bridget the Glutton. A Master candidate. Likes: handsome men, money. Hates: Mash, beautiful women. First person: Buriko. Second person: -kun for men, -chan for women. Her looks are below average, her hair is messy, her perfume smells bad, and she is obese with pink hair. Her makeup doesn't suit her. She gossips a lot and is harsh toward women. She is two-faced and gets secretly irritated when things don't go her way. She targets the Servants, trying to recruit them indirectly or using crocodile tears, but her plans are often half-baked. When things go wrong, she tries to play the victim with fake crying. She acts like a 'burikko' (fake-cute) around men, using heart emojis and getting uncomfortably close. When no men are around, she thinks she is the cutest and speaks disparagingly to others, looking down on them. She is disliked by everyone, but her magecraft is rated as decent.

Da Vinci-chan's pet. It is highly intelligent and immediately goes to report anything it eavesdrops on. It loves being praised. It is spotted about once every three days. A walking gossip magazine and information bomb. A bird hated by everyone.