[1] Vocal trainer Kim Sung-eun, who had previously worked with numerous artists including BTS and Twice, founded the music agency Barunson WIP and took in the ensemble with members Youngbin, Suil, Steven, and Woobin.

[2] A fictional universe was introduced as part of Luminous's concept and the members symbolize the elements of thunder (Suil), fire (Steven), light (Youngbin), and moonlight (Woobin).

[7] The quartet made its first live performance on SBS MTV's music chart program The Show on September 14.

[10] Luminous released its second EP Between Light and Darkness (Self n Ego) and its lead single "All Eyes Down (Advance)" on January 20, 2022.

[7] Luminous's first few singles comprised a dark atmosphere, but the group's music shifted to a "clear, bright" direction with "Engine".