Mai Zenin

Gender: female
Species: human
Height: 170 cm
Hair color: black
Occupation: Shaman, Student
Affiliation: Kyoto Jujutsu High School
Grade: Grade 3 Sorcerer
Cursed Technique: Construction

A second-year at Kyoto Jujutsu Technical High School. Mai was born to the Zenin Clan as the younger twin sister of Maki. As a child, Mai always relied on Maki since she was afraid of Cursed Spirits.

Because Mai and Maki are monozygotic twins, their strength is considerably limited to one another. Monozygotic twins are considered as a single individual in the Jujutsu world and are a sign of bad omen.

In chapter 149, Mai decides to sacrifice herself in order to make Maki stronger.
(Source: Jujutsu Kaisen Wiki)