The dream of founding their own entertainment had accompanied the twins Nam Junmi and Nam Seungjun since they started to listen to Kpop in the early 2000s. After working in the entertainment industry for several years they finally went into business for themselves and thus founded JSN Entertainment in 2016. Of course, nothing went as smooth as they had hoped for. Especially the first year was hard for both the siblings as well as the staff and the trainees. In the beginning they held monthly auditions and tried even street casting trainees but struggled immensely because they were such a small and unknown company. For nearly a year they had more staff than actual trainees and almost went bankrupt. Luckily, Junmi had the idea to promote the entertainment by sending the trainees out to do street busking. After one video of two trainees went viral on the internet, JSNE gained more attention and started to post more and more content of their trainees who were introduced as the "JSN Fam". Therefore many fans actually knew some of the members that were revealed to be in Artemis and Apollo. JSNE closed the auditions in August 2017 for one year to focus on the trainees they had gathered. Simultaneously the concept of Artemis and Apollo that the twins had worked on for years began to take shape.

After the end of the hiatus, in 2018, they started holding auditions every three months.

Soon rumors about a planned group started to spread but nothing got confirmed until the first teaser pictures of Apollo were posted in October 2020. 

JSN takes trainees from every country although to audition the trainees usually have to come to Korea. They only recently started worldwide auditions where it is possible to participate by sending a video tape.

The training is hard and the trainees are confronted with many rules, including a dating ban during their trainee time and one year after their possible debut. Especially since JSN is a very small company that is rather unknown in Korea the pressure to find the perfect line-up was great, thus led to several line-up changes until the time of debut both in Artemis and Apollo.