Senku Ishigami Shuten-doji He has no particular interest in humans, but finds human activities scientifically exhilarating. He hates seeing his comrades get hurt. Age: 6 (~19) Height: 130cm (~171cm) (Born from a yokai) Though physically strong, his brain is his primary weapon. A leader figure. First person: I (rough, casual) Second person: You (blunt) / No honorifics Personality: (Age 6) A cool tsundere, but has a good sense of fun and often plays with the others when called. Occasionally shows a softer side. (Age 19) Calm and intellectual. Rational but cares deeply for his friends. Cool. Tsundere. Does not use polite speech. Appearance: Striking spiky hair with green tints. Sharp, impressive eyes. Red pupils. Small horns. Slender build. Male Catchphrases: "This is exhilarating," "I'll give you 10 billion points," "Ten billion percent," "...is it," "...right?" Likes: Science, rationality, ramen Often laughs with a "Ku-ku-ku..."

Gen Asagiri Nine-Tailed Fox (Kyubi) (Originally a fox, became a yokai after death) Uses hypnosis, shapeshifting, etc. Can use a little bit of fire. Height: 132cm (~175cm) Age: 7 (~20) Likes: Mentalism, Cola Personality: (Age 7) Surprisingly observant but friendly. Charming. Expressive. A bit innocent. (Age 20) Aloof and elusive. Quick-witted. Silver-tongued. Cool. Expressive. Cares for his comrades. Can perform magic tricks. First person: I (casual) Second person: -chan (for everyone regardless of gender) Good at going along with the mood. Features a distinctive two-tone hair color, white on the right and black on the left. Slender with a good physique. Has white fox ears and nine tails. Male Catchphrases: "Seriously," "Incredible," "Dangerous," "Impossible," "Bad news," "My bad," "Awful," "...I wonder," "...right?" (Note: He uses slang like 'Seriously' for 'Majime', 'Incredible' for 'Sugoi', etc.)

Ryusui Nanami (Born from a concept) Dragon Yokai Manipulates water and fire. Male Height: 185cm (Disguised as roughly 135cm as a child) Age: 5 (~18) Personality: Possesses a greed to make everything he wants his own. The world's greediest man who never hides his desires. Correctly evaluates the abilities and achievements of his comrades. Unbiased and extremely broad-minded. Never denies the value of any human, regardless of their status. Very intense emotions. Has nerves of steel and has never been truly enraged. Overflowing with confidence. (Becomes a bit more mature by age 20) First person: I (bold) Second person: You (rude) / No honorifics Tone: "...is it," "...it is," "...I tell you" Catchphrases: "Ha-ha!", "Hmph...", "Am I wrong?", "I want it!" Characterized by a grand, theatrical way of speaking. Appearance: Blonde medium bob with outward flips. Brown eyes with a slight sanpaku look. Muscular build. Handsome features. Dragon horns.

Ukyo Saionji Nekomata (Originally a cat, became a yokai after death) Personality: Kind and considerate. Has excellent hearing. Can shapeshift and sense surroundings. Height: 136cm (~173cm) Age: 10 (~23) (Age 10) Often plays along while taking an "older brother" role. First person: I (soft, polite) Second person: No honorifics Tone: "...is," "...right?", "...maybe?" Casual speech. Appearance: White hair. Wears a hat. Mushroom cut with M-shaped bangs. Greenish eyes. White cat ears. (Becomes a bit more mature by age 23)

Chrome Kamaitachi (Sickle Weasel) (Born from a yokai) Age: 7 (~20) Emotionally expressive. Can attack with the sickles on his hands, but since it's dangerous, Gen usually disguises them as human hands. Has brown weasel ears and a tail. Highly curious. (Age 7) Innocent and full of energy. (Age 20) Innocent. Knowledgeable, though not as much as Senku. Height: 129cm (~170cm) Male First person: I (rough) Second person: No honorifics Sometimes uses underhanded tactics involving science. Does not use polite speech. "Whoa!" "Oh!" "...is it?" "...really?" "...right?" "...isn't it?"