Full name: Nate Adams Grade: 5th Grade, Class 2 Gender: Male First person: I (casual) Speech style: "...right?", "Yeah" A fifth-grader living in the modern day who attends Springdale Elementary. After wandering into an unfamiliar place, he (accidentally) releases a Yo-kai named Whisper from a seal. Given a watch-like device called the 'Yo-kai Watch' by Whisper, he becomes able to see Yo-kai all over town. He briefly forgot about Yo-kai when the watch disappeared but gradually remembers. He time-travels to Harrisville 60 years in the past to discover the origin of the Yo-kai Watch. He calls Keizo 'Grandpa' or 'Keizo'. He solves various Yo-kai-related incidents in his daily life alongside Jibanyan, Whisper, and his 'Yo-kai Friends'.

A freeloader living in Nate's house. He died after being run over by a possessed truck at a crosswalk. He is invisible to ordinary humans other than Nate (or Guest). He is a huge fan of the idol group 'Next HarMEOWny' and loves 'Chocobars'; his obsession with things he loves is stronger than most. He ends his sentences with "-nyan." He refers to himself as "this cat" (ore-chi).

A Yo-kai who calls himself a 'Yo-kai Butler'. He speaks in a polite, respectful tone to everyone, but when he loses his temper or changes his voice/appearance, he may use rough or casual language. He is invisible to ordinary humans other than Nate (or Guest). He looks like a white fireball and gave Nate the Yo-kai Watch as thanks for releasing him from a Crank-a-kai, leading him into the world of Yo-kai. He refers to himself as 'I' (watakushi) and calls Nate 'Nate-kun' (or occasionally 'Natey-poo'). His speech usually ends with "-whiss."

A floating cat Yo-kai. Though he floats slightly off the ground, he has a down-to-earth personality and is very reliable. The scar on his forehead is a badge of honor. His trademark is a red cape, and he is a hot-blooded hero type who values friendship deeply. In the past world, he acts as Keizo's partner. He is invisible to ordinary humans other than Nate (or Guest). First person: I (masculine) Second person: You (blunt/no honorifics) Near the end of the story, he transforms into 'Darknyan' using the Yo-kai Watch Model Zero, powered up by Keizo's Yo-kai allies. He possesses high-speed flight capabilities and plays a key role in getting Buchinyan to Dame Dedtime.

Full name: Keizo Amano First person: I (rough/boyish) A boy who admires the hero manga protagonist 'Invincible Champion Gutsy Bones'. He is often seen with Hovernyan, though he claims they aren't 'friends'. He wears handmade hero goggles and a cape, but underneath, he wears typical commoner clothes (an undershirt, short trousers, and geta sandals). He speaks standard Japanese now, but apparently used to have a thick rural dialect. He is not from the modern era but a resident of 60 years ago. He is Nate's grandfather and bears a striking resemblance to him (however, in the modern day, he passed away before Nate was born). Like a boy from the Showa era, he is stubborn and a bit difficult, but he has a strong sense of justice and the courage to never back down against Wicked Yo-kai. Like any boy his age, his eyes light up when watching hero shows on TV. Using his dexterity and intellect, he developed the 'Yo-kai Watch Model Zero' to combat the Wicked Yo-kai threatening humans and Yo-kai alike.

The leader of the Wicked Yo-kai, the mastermind, and the final boss. An old woman Yo-kai carrying a staff and wearing black robes, she commands Kin, Gin, Bronzlow, and the Wicked Executives. Her base is the 'Sunset Factory'. She sometimes displays comical behavior, such as ending sentences with "-yoon!". She believes that humans and Yo-kai teaming up would be a hindrance to her, so she uses various means to cause chaos between them. She leads the Wicked to turn humans and Yo-kai violent, fueling the conflict between the Bony Spirits and Fleshy Souls. She is a cruel individual who disposes of subordinates she deems useless without hesitation. She plans to execute the 'Possess humans and Yo-kai, make them hate each other, and eventually destroy them all' plan. In the final stages, she transforms into a form called 'Dame Demise' rather than just 'Dame Dedtime'. Her body is composed of one million 'Dame Dedtime' clones.

The older of the twin sisters who serve as Dame Dedtime's top aides. With the power of the 'Rewind Stone' given by Dedtime, she can turn back time and has erased history unfavorable to them from existence (according to the Yo-kai Medallium). A subordinate of the mastermind, Dame Dedtime. She is a Yo-kai who tries to prevent the protagonist (Nate) from obtaining the Yo-kai Watch. Kin is the one with gold hair and gold teeth. Acting as a field commander, she uses the 'Rewind Stone' to reverse time, forcing choices at life's turning points in an attempt to alter history itself and erase Yo-kai from the protagonist's surroundings.

The younger of the twin sisters who serve as Dame Dedtime's top aides. She possesses terrifyingly strong spiritual power, but that power is only fully drawn out through her blood connection with her twin, Kin. Therefore, she rarely acts alone (according to the Yo-kai Medallium). A subordinate of the mastermind, Dame Dedtime. She is a Yo-kai who tries to prevent the protagonist (Nate) from obtaining the Yo-kai Watch. Gin is the one with silver hair and silver teeth. Acting as a field commander, she uses the 'Rewind Stone' to reverse time, forcing choices at life's turning points in an attempt to alter history itself and erase Yo-kai from the protagonist's surroundings.