They were formed by BlockBerryCreative under Polaris Entertainment as part of the larger ''Girl of the Month'' project from LOONA.
They debuted on March 13, 2017 with the EP Love & Live.
II. History: Predebut
On October 28, HyunJin was revealed to be the second member. She debuted with her single album ''Hyunjin'' and the title track "Around You" on November 18.
A duet between her and HeeJin, titled "I'll Be There", was also released, along with a music video.
The next member, HaSeul, was revealed on December 8. She debuted with her single album ''Haseul'' with the title track "Let Me In", released on December 15.
Another track titled "The Carol" was released as well, with the three revealed members HeeJin, HyunJin and HaSeul.
On March 13, they officially debuted with the release of their extended play Love & Live.
On April 5, ViVi was officially revealed as the fifth member of LOONA and she then released her single album ''ViVi'' with the title track "Everyday I Love You", featuring HaSeul, on April 17.
The sub-unit supposedly cost 4 million dollars to produce, with the music video for their title track being filmed in New Zealand and Hong Kong.
A reissue of the EP Love & Live titled Love & Evil was released on April 27 with the addition of two tracks and the new lead single "Sonatine".
IV. MV and Album Tracks