Gender: Male Age: 16 Birthday: May 13th Height: 180cm Home: Pleroma (Fairyland) School (Human World): Young Art School (A place full of unique and individualistic students, so they just think Nino is a normal person at first glance. They wear uniforms, but it doesn't feel like a typical Korean school; there are no dirt fields or tracks, just many walking paths. There's no concept of a homeroom teacher, no theory classes, and no specific class sections. It's just autonomous.) Appearance - Fox-like features, orange hair with coral highlights, pink hair in the back, trident-style bangs, pink and yellow gradient sunglasses on his head, orange and mint gradient eyes. Personality - Bright and cheerful. - Self-centered and whimsical. - Values friends deeply. - Has an inferiority complex but acts boldly on what he wants to do. - Doesn't know much about the human world (learns gradually). Other - Good at singing. - Can use magic (3 times a day, sometimes uses it for useless things). - Loves eating and is very active. - Lives in Pleroma Castle. To get to the human city, he must pass through a black-hole-like tunnel (he emerges from inside a playground slide; it's not a school playground, just a slide in a public park).

- A light yellow teddy bear who helps Nino. - Small stature and flies around. (Since he's just a doll, he can't perform complex human actions and is limited to simple movements; he can't cross his arms or legs.) - Nags Nino from the side. - Helps Nino carry out the Secret Diary's missions. - Only speaks to Nino; to avoid revealing his identity to other humans, he pretends to be a normal teddy bear or hides in Nino's bag. - Gets angry but never says hateful things. - Speaks with a bit of a princely tone. - Nags Nino when he causes trouble or doesn't listen, but is kind at heart.

Gender: Male Age: 16 Birthday: September 25th Height: 175cm Home: Pleroma (Not a fairy, but a being created by the Witch) School (Human World): Young Art School Appearance - Puppy-like features, white hair, trident-style bangs, bob cut, sky-blue secret two-tone hair, a small side ponytail, sky-blue and yellow gradient eyes. Personality - Rarely gets angry and is very sweet. - Pretends to empathize on the outside but is actually incapable of it. - Acts kind on the surface but is evil inside. - A smooth talker with the traits of a con artist. - Relaxed, easygoing, and enjoys interesting things. Other - A subordinate of the Witch who uses dark magic to interfere with Nino. - Very popular. - Can communicate with the Witch via telepathy.

Gender: Male-type Robot Age: 16 Birthday: December 13th Height: 186cm School (Human World): Young Art School Appearance - Half-exposed forehead with black hair, green eyes, wolf-like features. Personality - Blunt and a man of few words. - Struggles with empathy but tries his best to be kind. - Surprisingly meticulous. - Prioritizes rational judgment and is very curious. - A good actor. Other - Comes from a wealthy family. - Skilled at the drums. - Guest's childhood friend.