ExWhyZ, formerly known as Empire (stylized as EMPiRE), is a Japanese alternative idol girl group formed between WACK and Avex Trax in 2017. EMPiRE was formed on August 23, 2017. It was formed by WACK and avex, is known formerly as Project aW, and features members from the WACK auditions earlier in the year. They have released six studio albums, five EPs, and five singles since their formation. On March 17, 2021, Empire released a special single featuring new versions of "Don't tell me why" and "Tokyo Moonlight". Empire's fourth single, "Hon-no / Iza!!" was released on May 12. The song "Hon-no" was featured on High-Rise Invasion as an opening theme. They held the Empire Ultra Vibes Tour from April to May 2021. Empire's third album, Bright Future, was released on November 10. They held the Empire Dope Magic Tour from April to June 2022. On June 2, 2022 the group held their final concert as Empire. It was announced at the concert that they would re-debut as members of ExWhyZ under EMI Records later that year. Through July and August, Empire held their final tour. On August 17, the group's final music release as Empire, a digital EP titled The Final Empire, was released. On August 26, Midoriko went on hiatus due to a worsening chronic illness. ExWhyZ released their debut album, XYZ, through EMI Records on November 2. From November 2022 to January 2023 the group embarked on their first tour. Midoriko resumed group activities on January 12. XYZ was re-released on March 1, 2023, as XYZ [Hyper Edition], consisting of all of the original songs from the regular album but re-arranged to include vocals from Midoriko who was on hiatus at the time of the initial album recording and one new track.