Eir Aoi (藍井 エイル, Aoi Eiru, born November 30, 1988) is a Japanese singer from Sapporo, Hokkaido, signed to SME Records. After being discovered through the Japanese video sharing website Niconico, Aoi made her major debut in 2011 with the release of her first single "Memoria", whose title track was used as the first ending theme to the 2011 anime television series Fate/Zero.
Aoi's music has been featured in various anime television series such as Fate/Zero, Sword Art Online, Kill la Kill, and The Heroic Legend of Arslan, as well as various television programs such as Rank Okoku. Aoi has also performed at various anime conventions in the United States, Southeast Asia, and Europe. In October 2016, following prolonged bouts of poor health, Aoi announced an indefinite hiatus from musical activities following a two-day concert at the Nippon Budokan in November 2016.
Aoi began her singing career in a band she formed in high school. After being discovered through the Japanese video sharing site Niconico, she released her debut single "Memoria" on October 19, 2011, which was used as the first ending theme song to the 2011 anime series Fate/Zero. Her second single "Aurora", which was released on September 5, 2012, is used as the fourth opening theme song to the 2011 anime series Mobile Suit Gundam AGE. Her third single "Innocence", which was released on November 21, 2012, was used as the second opening theme song to the 2012 anime series Sword Art Online. Her first album, Blau, was released on January 30, 2013. Aoi made an appearance at Seattle's Sakura-Con anime convention in March 2013.
Aoi's fourth single "Cobalt Sky", was released on June 26, 2013. Her fifth single, "Sirius", was released on November 13, 2013, and was used as the first opening theme to the 2013 anime series Kill la Kill. Her song "Sanbika", released on the same single as "Sirius", was used as an insert song throughout the series. Aoi's sixth single, "Niji no Oto" (虹の音, Sound of the Rainbow), which was released on January 1, 2014, was used as the opening theme to the special Sword Art Online: Extra Edition. Her seventh single "Ignite", released on August 20, 2014, was used as the first opening theme to the 2014 anime series Sword Art Online II. Her eighth single "Tsunagaru Omoi", released on November 12, 2014, was used as the opening theme for the TBS show Rank Okoku. Her ninth single, "Genesis", released on February 18, 2015, is used as the ending theme to the 2015 anime series Aldnoah Zero:2nd Season. Her tenth single "Lapis Lazuli", released on April 22, 2015, was used as the ending theme to the 2015 anime series The Heroic Legend of Arslan. Her twelfth single "Cynthia no Hikari" (シンシアの光, Cynthia's Light), was released digitally on March 25, 2015, and is used as the opening theme of the 2015 video game Sword Art Online: Lost Song. Her third album "D'Azur" was released on June 24, 2015. Aoi cancelled a scheduled appearance at Animelo Summer Live in August 2015, although she pushed through with appearances in the Philippines, Hong Kong, Taiwan, and Singapore later that year. Her eleventh single, "Shoegazer", was released on October 28, 2015.
Her twelfth single "Accentier", was released on March 2, 2016 and is used as the opening theme for the PlayStation Vita game Digimon World: Next Order. Her thirteenth single "Tsubasa" (翼, Wings) was released on July 20, 2016, and was used as the opening theme for the second season of The Heroic Legend of Arslan anime. Her first and second greatest hits albums titled "BEST -E-" and "BEST -A-", were released on October 19, 2016 in commemoration of the 5th anniversary of her career.
On August 17, 2016, it was announced on her official Facebook page that she would put her career on hiatus due to poor health. Her remaining appearances for 2016 and a scheduled performance at Animax Musix 2017 in Osaka in January 2017 were cancelled. On October 14, 2016, Aoi's management announced that she would put her musical career on indefinite hiatus following a two-day Nippon Budokan concert on November 4 and 5, 2016.