2020: Debut with Pre Episode 1 : Door
On August 27, OSEN reported that Maroo had finished preparations for the debut of their new boy group in September. The agency confirmed the news, stating that the group will consists of nine members including members of the unit group TEEN TEEN.
At 12AM KST on September 1, a logo motion video was released on their YouTube channel, revealing the group's official name to be GHOST9.
|Hwang Dong Jun (황동준)||Main Vocalist, Rapper||2020–present|
|Lee Woo Jin (이우진)||Vocalist||2020–present|
|Shin (신)||Main Dancer, Vocalist||2020–present|
|Choi Jun Seong (최준성)||Main Vocalist, Main Dancer||2020-present|
|Lee Jin Woo (이진우)||Rapper, Lead Dancer, Sub-Vocalist, Maknae||2020–present|
|Lee Kang Sung (이강성)||Rapper, Lead Dancer||2020–present|
|Son Jun Hyung (손준형)||Lead Vocalist, Main Dancer||2020–present|
|Prince (프린스)||Vocalist, Lead Dancer||2020–present|
|Lee Tae Seung (이태승)||Lead Vocalist||2020–present|
- Pre Episode 1 : Door (2020)
- Hwang Dong Jun originally debuted as a soloist in 2017 under the name $ept Rabbit.
- Lee Woo Jin, Choi Jun Seong, Lee Jin Woo, and Lee Tae Seung were former contestants on Produce X 101.
- Lee Woo Jin, Lee Jin Woo and Lee Tae Seung are also members of the unit project group TEEN TEEN.
- Son Jun Hyung was a former contestant on MIXNINE.