Mei Mei has long, pale blue hair that extends past her shoulders, with two braids, one that hangs in front of her face and the other behind her head. She also has thin eyebrows.
Mei Mei wears a black long sleeved, high collar dress with black shoes.
In her casual outfit, Mei Mei has her hair in a single braid and wears a light colored dress with no shoulders.
As a student, Mei Mei kept her hair in a ponytail and wore a black long sleeved shirt with a light colored tie, black pants, and black shoes.
While playing ping pong, Mei Mei has her hair in a single braid and wore a white short sleeved polo with a black collar, along with black shorts and black shoes.
Years ago, Mei Mei along with Utahime are on a mission when they are trapped within a spirit's barrier. As Mei Mei and Utahime discuss what to do, Gojo, Geto, and Shoko show up and free the two from the barrier along with exorcising the spirit. After being freed from the barrier, Mei Mei asks them were the screen is. After the mission is complete, Mei Mei and Utahime head back to the college.
Kyoto Goodwill Event Arc
Mei Mei watches the Kyoto Goodwill Event along with the other faculty. While watching the event, Mei Mei notices how strong Maki is and wonders why she had not been promoted which Gojo tells her that Maki's family is getting in the way of Maki's promotion. Gojo then brings up how he can't see Yuji's fight, which Mei Mei give him a simple excuse.
When intruders invade the event, Mei Mei is told to locate where all the students are at while others go handle the intruders. After the invasion, Mei Mei attends a meeting with the other faculty, where they are informed casualties they have sustained and what was stolen. After the Kyoto Goodwill Event is finished, Mei Mei heads back to Kyoto with the other faculty and students.
Death Painting Arc
Days later, Mei Mei checks her bank account and sees that Gojo has deposited 10 million into her account. Later, Mei Mei and Aoi meeting with principal Yoshinobu in order to promote Maki and Panda to Grade 1 Sorcerers. Later Mei Mei plays a game of tabletop tennis with Aoi. As Aoi voices how he will be able to join Yuji on his mission, Mei Mei tells Aoi that the person who nominated a person can't accompany the nominee on missions. After telling Aoi this, Mei Mei leaves.
The Shibuya Incident Arc
On October 31, Mei Mei is with her brother Ui Ui and Yuji at Aoyama Cemetery while Gojo handles the situation at Shibuya. Suddenly Mei Mei receives a call about a certain appearing at Meiji-Jingumae Station, and Mei Mei, Ui Ui, and Yuji head over their to check on the situation. Once they arrive at Meiji-Jingumae Station, they are informed about the situation at the station. After being informed, Mei Mei uses her power on some crows to investigate what is happening in the station. Once she gets enough information and her crows are killed, Mei Mei informed Yuji and Ui Ui what is happening in the station. When Yuji asks if Mahito is in the station, Mei Mei tells him that she doesn't know but he might be since their are mutated humans in the station. Mei Mei then tells Yuji that they will split up, which Mei Mei and Ui Ui enter through one entrance while Yuji head in through another. Once they reached their location, Mei Mei manages to protect some humans from Mahito's mutated humans. When the curtain is raised, Mei Mei decides to heads over to platform B5F with Ui Ui and wait for Yuji.
Once Yuji arrives at their location, the three head off to where the trapped people are at. Along the way Mei Mei tells Yuji that he is good enough to be a first grade Sorcerer and that she hasn't seen anyone get this far without using techniques Kusakabe, which Yuji accepts her compliment after Ui Ui get angry at him. Once they arrive at the station the people are trapped at, they notice that there is only one person present. Mei Mei, along with Yuji and Ui Ui, then head towards Gojo's location, but stop when Yuji is suddenly contacted by Kokichi. Mei Mei along with Yuji and Ui Ui listens as Kokichi explains how Gojo has been sealed, that he has been killed days before, and that he has set up a back up plans just encase he had been killed. As Kokichi explains how he had ruled out Yuji and Mei Mei are the other mole, which Mei Mei wonders why she was ruled out. Kokichi says that Mei Mei had went to Mejijingu-mae station instead of staying on standby in Shibuya. Mei Mei says that she might not be following orders, which Kokichi asks why there are cursed users following them.
Mei Mei notices that there are two of them following and asks Yuji if they are stronger than the spirit that he faced, which Yuji says that the two are stronger. Mei Mei wonders where the Cursed users were hiding but says that they should continue on. Kokichi tells them that they can't since there is a screen that won't let Sorcerers through ahead of them. Kokichi says that Mei Mei will have to open a path, so that Yuji can head back and head towards Gojo's location from above ground. When the Cursed users show up, Mei Mei along with Yuji and Ui Ui prepare to fight them. As Mei Mei fights her enemy, she explains how her technique works and what she had done to get so strong. As the enemy surrenders, Mei Mei asks what use can he be for her but kills him when he doesn't answer her right away. Afterwards, Ui Ui tells his sister that the curtain is down, which the two continue down the tunnel.
After a while, Mei Mei and Ui Ui run into Geto. Mei Mei and Geto start to talk, while Mei Mei also thinks about why Geto is still alive. Mei Mei figures that this Geto is a fake but think against this when Geto summons a cursed spirit. Geto then leaves, after having Mei Mei face off against his cursed spirit. As Mei Mei faces the cursed spirit, Smallpox Deity, the spirit uses its territorial expansion to seal Mei Mei in a coffin. The spirit also crushes Mei Mei with a large boulder, but Mei Mei is able to break the boulder before it can kill her. Mei Mei then wonders how long its been since her life has been in danger. Mei Mei manages to break free from a couple more of Smallpox Deity's attacks and manages to figure out how Smallpox Deity's attacks works. Mei Mei has Ui Ui distract Smallpox Deity long for her to attack the spirit. As Smallpox Deity attacks Mei Mei, she has one of her crows exorcise the spirit at the cost of its life. Once they are released from the spirit's domain, Mei Mie and Ui Ui prepare to face off against Geto.
Mei Mei uses a large axe when facing against curses.
Cursed Technique: Mei Mei's Cursed Technique is called Black Bird Manipulation. Mei Mei is able control crows as well as to see what the crows under her control are witnessing.
- Bird Strike: by forcing a crow to commit suicide, the trade off is to erase the Cursed Energy limit of a typical weak bird and hurl it at the enemy. Currently only Satoru Gojo has survived this technique.
- Mei Mei's name contains the kanji for "dark" (冥 mei?).
- Mei Mei ranked 47th place in the manga's 1st Character Popularity Poll with 163 votes.