The EP contains the lead single "Black Mirror", a rock version of their debut song "Valkyrie", and three new tracks. Group member Ravn co-wrote the lead single "Black Mirror".[1]
Puah Ziwei, writing for NME, noted that the lead single "Black Mirror"'s music video "seem to draw inspiration from the late Michael Jackson" and the "lyrics also reference a number of the late pop icon's hits, including 'Bad' and 'Man In The Mirror'."[1]
The EP ranked at number 2 for the weekly Gaon Album Chart[2] and number 4 for the monthly chart.[2] The EP sold 103,240 copies in South Korea by the end of June 2021.[3]
In addition, Black Mirror has been listed as one of 'The Best K-Pop Tracks of 2021' by Dazed. Dazed stated " There's the slap of funk bass and washes of strings, elements that comprised the backbone of 1979's Off The Wall, but ONEUS's composers have recalibrated the analogue into a cool, impersonal sheen of digital production. It's a canny twist; a thumping, computerised nu-disco backdrop for the song's flesh and blood lament – the loss of human connection within the technological age."[4]
^ abc2021년 20주차 Album Chart [Album Chart for Week 20 of 2021]. Gaon Music Chart (in Korean). Archived from the original on May 20, 2021. Retrieved April 10, 2022.
2021년 상반기 Album Chart [First Half of 2021 Album Chart]. Gaon Music Chart (in Korean). Archived from the original on June 10, 2021. Retrieved July 9, 2021.
