Japanese pop/rock singer and lyricist Aimer built a huge following in Japan, and a sizeable one in the West. Her highly melodic songs range from ballads to hard rock, while her rich, expressive alto voice, breathy and slightly husky, can swoop from fragile displays of emotion to powerful shows of force.

Born and raised in the small southern city of Kumamoto, the child of a rock bassist father, Aimer grew up surrounded by music. She began singing and playing piano at an early age and took up the guitar in high school. At age 15 she damaged her voice through overuse and had to undergo silence treatment. After recovering, she was left with her trademark slightly husky voice and a renewed certainty that she wanted to commit to music as a career. Her stage name is the French verb meaning "to love."

After joining the AgehaSprings management group, her career took off when she was signed to DefStar Records, a Sony subsidiary. Her first album, Sleepless Nights, appeared in 2012 and was an immediate hit, just missing the Oricon Top Ten. Midnight Sun followed in 2014, cracking the Top Ten, while 2015's Dawn saw her hit the Top Five for the first time. Her following four albums all cracked the Top Three. 2016's Daydream was her first for SME Records, after DefStar was folded into that label; 2019 saw the simultaneously released Sun Dance and Penny Rain; her seventh album, Walpurgis, was released in 2021. She also released two mini-albums, three compilations, and dozens of singles.

Aimer is usually considered part of the "anison" (anime songs) scene of music made primarily as theme songs for anime shows and films, which are hugely popular in Japan. Mostly performing ballads for the early part of her career, she gradually worked on strengthening her voice and branching out into heavier, hard rock material. Her highly melodic songs, for which she writes most of the lyrics, tend to have a fragile vulnerability and melancholy, even in the heavier numbers. The music for many of her songs is written by famous anison composer Hiroyuki Sawano.

Intensely private and shy, Aimer never revealed her real name and didn't even reveal her face for the first five years of her career, performing on dimly lit stages and always photographed from oblique angles to ensure the focus remained solely on her voice. She eventually showed herself in 2016 on a TV music show, and gradually began doing more press.

A thoughtful and introspective artist intensely focused on self-improvement in her craft and on achieving the very best results each and every time, Aimer was the very opposite of the stereotypical, ego-driven pop star. Her shy, self-effacing manner, warmth, and generosity of spirit aroused a fierce passion in her fan base, who supported her obsessively. Despite recording almost exclusively in Japanese and never signing a Western record deal, she also developed a devoted following in the West through streaming services, online forums, and anime fans. ~ John D. Buchanan