S.I.S

S made their first public appearance with their participation in the inaugural IDOLcon event. On August 25, 2017, the group officially made their debut with their first single album "I've Got A Feeling". In September, the members auditioned for The Unit, with only Anne, Gaeul, and Sebin passing the auditions.

Sebin got eliminated in the first round at 55th place, Gaeul got eliminated in the second round at 39th place while Anne reached the final elimination round and placed 22nd. On October 18, XX Entertainment launched the group’s first Makestar project to crowdfund their next comeback. The project ended on March 31, 2018, surpassing its goal by 124%.

In early 2018, S. I. S performed at various events across South Korea, Japan, and Malaysia.

The group returned on September 20 with their second digital single, "Say Yes", following promotional teasers and the success of their earlier Makestar project. On December 13, the group opened thair second crowdfunding campaign on Makestar. In just four hours the project reached its goal and went on reach 312% by the due date on February 8, 2019.

On February 10, Dal made her solo debut with the digital single "Sad Love Story". As part of their second Makestar project, a comeback schedule was revealed on February 21, confirming the release of their third single album, "Always Be Your Girl", which was later released on March 6. On July 12, XX Entertainment announced that J-Sun’s contract had expired and that she had chosen not to renew it in order to focus on her studies.

They also revealed that Dal would be going on a temporary hiatus due to personal reasons. As a result, the group would continue promoting as four. On August 6, a third crowdfunding project for S.

I. S's comeback was launched on Makestar. Once again, it surpassed its goal, reaching 259% of its initial target.

By April 2020, Dal was no longer listed on the group’s social media, indicating her unofficial departure. On July 20, an individual teaser for Minzy was released, following the conclusion of the group’s third Makestar crowdfunding project. The teaser confirmed S.

I. S's comeback with their fourth single album, which was eventually released on July 31, titled "Don't Wait". On October 8, it was announced that Minzy would be taking a temporary break from activities.

In February 2021, S. I. S became models for the flower delivery brand 7788Flower.

The CFs featured Minzy, Anne, Sebin, and their labelmate Ria from BOTOPASS. In March, the group’s Facebook page was deleted and their Instagram was set to private. Other accounts remained inactive, and no official statement followed.

This led to the presumption that the group had quietly disbanded. Following the disbandment of S. I.

S, the members went their separate ways. - On December 29, 2020, J-Sun, now promoting under the stage name Ellia, announced the release of her first digital single, marking her debut as a soloist and DJ. The single, "Belongs To You" had already been released a week earlier, on December 21.

- Dal, now using both the names Kim A Hyeon and Jerry, launched her own YouTube, Twitch, and Instagram accounts. Most of her content consists of vlogs, produced in partnership with Seoul Streaming Station. She is currently dating a non-celebrity and has featured in various songs since leaving S.

I. S. She is also active in a Catholic choir.

- Minzy started working as a model and dancer. - Anne, now under the name of Jion, became active as a model. - Gaeul and Sebin appeared to have left the entertainment industry and are focusing on their personal lives.