Tachibana Ren is cosplaying as Meiko from VOCALOID.

MEIKO is a Vocaloid DTM (Desktop Music) software created by Crypton Future Media. She is the first Japanese vocaloid and first Japanese female Vocaloid, she utilizes the Vocaloid engine developed by YAMAHA. Her voice is based on a Japanese female singer Haigō Meiko (拝郷 メイコ). The illustration was done by Shogo Washizu, who is often called わっしー(Wasshi) and was once a member of Crypton.

History
On July 24, 2003, an CCCD album "HISTORY OF LOGIC SYSTEM", which included a song using Subarashii Ai wo Mou Ichido (That Wonderful Love Once More)" and it was covered by prototype[3 version of Meiko and Kaito before their release. version of Meiko and Kaito before their release Nico broadcast 【VOCALOID遺産】あの素晴らしい愛をもう一度 Youtube broadcast【VOCALOID遺産】あの素晴らしい愛をもう一度 Crypton placed this product on the market with a box art which depicted Meiko in anime form. This character had nothing to do with the singer's image, but her appearance appealed to the mainstream audience and the software sold well. The success of this marketing strategy influenced the development and art style of other Vocaloids such as Kaito and Miku Hatsune.