The members of Dongkiz—Wondae, Kyoungyoon, Munik, Jaechan, and Jonghyeong—were trainees between one to three years. The group was modeled after New Kids on the Block. Dongkiz initiated promotional activities in August 2018, which included uploading dance covers onto Dongyo Entertainment's YouTube channel and busking. They also performed at the HEC Korea Concert in Thailand. Dongkiz released a Minneapolis sound-based pre-debut single entitled "Nom" on November 21, 2018. Soon thereafter, they performed at the Charity Concert for Palu, Sigi, and Donggala; its proceeds were donated to victims of the 2018 Sulawesi earthquake and tsunami in Indonesia. Originally slated for a February 2019 debut, Dongkiz released their debut single album "Dongkiz on the Block" on April 24. They intended to promote a different song, but ultimately decided on "Nom" to serve as the lead single. On July 22, Dongkiz released their second single album "BlockBuster". The title track samples the theme song of the 1984 film "Ghostbusters". Dedicated to their fans, Dongkiz released the dance-pop track "Dreaming You" as a digital single on September 11.