In her previous life, she was Kanami Okazaki (岡崎 香奈美), the homeroom teacher to the kids who were reincarnated, and they affectionately called her "Oka-chan."
After reincarnating, she began attending school with Shun and the others as their classmate. Since she reincarnated as an elf, she looks younger than she actually is.
She's a caring teacher who continues to follow her students after their reincarnation, but she has many secrets.
(Source: Official Site)