With the exception of U, who is Japanese and the only non-Korean member, all 5 ONF members have enlisted in December.

MK was the first to enlist, and on December 21, he arrived at the training center. "MK, who always gave us great energy!" reads a Twitter post from ONF, which includes images of MK with his members. He'll return to FUSE (ONF's official fan club) as the more reliable and cool ONF's MK and Min Kyun (MK's real name) even though he'll be gone for a time."

J-Us and Wyatt were the next to enroll, arriving at the training site on December 27. "When J-Us and Wyatt, who have always offered bountiful love to FUSE, return as trustworthy Seung Jun (J-real Us's name) and Jae Young (Wyatt's real name) after a few seasons, they will protect FUSE for the rest of their lives," ONF stated with photographs of the remaining five members. Until then, FUSE, pledge to be well! ”

Hyojin and E-Tion were the last to enroll in the military on December 28. "ONF's adorable orange boy E-Tion!" wrote ONF on Twitter alongside photographs of E-Tion. He'll be gone for a time, but as long as we fill our hearts with wonderful memories, you'll see him again soon! You'll be able to see Chang Yun (E-real Tion's name) in a new light! ”

"Hyojin, the warm and gentle leader of ONF!" reads the description on another Twitter post with Hyojin. We pledge that when the time comes for us to meet again, Hyojin and FUSE will be able to greet each other with bright smiles."

ONF debuted in 2017, and their sixth mini album "Goosebumps," released on December 3, marked their most recent comeback.