Fuu2 is a light-blue Yo-kai with Nate's hair in its top and face, it also has a star-shaped hole in its body, similar to the star on Nate's human form's shirt. His tail is curved into the shape of a '2', playing upon his name.
He has a body shape similar to Whisper, looking like a ghost.
When posing he sticks 2 fingers in the air, says his name, and flashes his "2" twice.
Fuu2's personality is identical to Nate's as he is very average in terms of Yo-kai and seems repentant when his power lands Yuto an average grade.
He has the habit of saying "Fuu~!".
Fuu2 has the power to make someone extremely average in all aspects. The hole in his chest can display memories that are "average", presumably meaning unfiltered by emotions or personal conceptions. When doing his introduction dance (which is an involuntary response to saying his name), he can flash the 2 shape tip on his tail like a light bulb.
As a ghost-like entity, he is capable of flight, cannot be seen without usage of the Yo-kai Watch and has ghost like chants which can be perceived by humans.
In M02, Nate falls down a manhole and dies. After he dies, the Yo-kai Watch disappears and he gets brought to the Yo-kai World to become Fuu2. Then he goes back to the human world and he befriends a human named Yuto Arima after giving him an average grade during his time as a Yo-kai.
In the Sukiyaki version there is quest called, "That is a World that Exists Somehwere" (Japanese: それはどこかにある世界,Sore wa doko ka ni aru sekai), in which Nate endes up being transported into a parallel world, where he turns into Fuu2, and teams up with that world's version of Katie, who possesses a Yo-kai Watch instead of him in that reality. In the 3.0 update, this quest gains a follow-up called "Battle of Women" (Japanese: 女の戦い,On'na no Tatakai), still limited to Sukiyaki. Within that quest, Fuu2 teams up with the other world's Katie once more, who has received an invitation to the Yopple company, where she meets her world's versions of Hailey and Usapyon.
In the movie, Fuu2 was created when Nate fell down a manhole due to the actions of Demon Okure summoned by Lord Enma in human form, by opening up a manhole to the Springdale Sewers as Nate skipped backwards in elation from saving Lord Enma. He was forcibly brought to a Yo-kai Center where he was assigned a name, Yo-kai form, Medal and a human to care for. After befriending said human and saving him from Demon Okure, who attacked him, Fuu2 was allowed to reenter his human body (as his injuries were capable of being lived through) and has now returned to being Nate.
User and allies have a good element against the enemies.
Fuu2 is a wordplay on the word Futsū (Japanese: 普通,"average", "normal") and "Tsu" (Japanese: ツー,Japanese phonetic spelling of the English word "two"). In the second movie, he was made right after the Yo-kai Fuu, meaning he is literally Fuu Number 2.