K-Pop Rookie Under Fire For Using Slur Against BTS' RM

13-year-old rookie rapper ACHILLO has come under fire for calling rapper RM a "Rap Retard."

The teen, who debuted in Starship Entertainment's youth hip-hop trio OGZ, made the comment in an old Facebook post unearthed by AllKPop.

"The Rap God has met with the Rap Retard," ACHILLO wrote in a Facebook comment as response to a collaboration between Dynamic Duo Gaeko and RM. "How will it be lol [sic] I'm only going to listen to Gaeko's verse."

(Photo: AllKPop.com)

RM, real name Kim Nam-joom and formerly known as "Rap Monster," is the leader and main rapper of hit South Korean boyband BTS.

ACHILLO drew ire from BTS' loyal ARMY — or “Adorable Representative M.C for Youth” — who called out the young rapper on social media.

Twitter user mochulattae responded to the teen's comments in a since-deleted tweet, saying the rapper "just ruined [his] career."

kid??? youre just 12 but you said this such things?? i dont get it. youre young but you talk bad already for a kid. im sure RM is fine for being critized but you just ruined your career? and youre a newbie, a rookie. what do you want? unsuccessful debut??? wow.

In response, ACHILLO went on a lengthy tirade, claiming he was only airing his "personal thoughts."

"Hello I'm sure as a fan you'd get upset that I called Rap Monster a Rap Retard. I'm so sorry about that," ACHILLO wrote. "Why do you like Rap Monster? I don't understand."

"I was only writing out my personal thoughts when I said that Gaeko and RM collaborating is like someone who can't rap collaborating with the best rapper in all of Korea," the rapper added.

"I understand you can be upset that I called him a Rap Retard," ACHILLO reiterated, telling the recipient, "you better delete the post."

BTS fans criticized ACHILLO on Twitter, while others called for understanding.

"He was wrong clearly, but firing him back isn’t a good way to teach him a lesson," wrote Twitter user aaaadjsth. "Let his company and parents do that part. I know he made a mistake but he’s human too and what if it triggers him to do something very dangerous because of the foul comments."

"[I] agree that he shouldnt [sic] be bullied, but using the r word is also not something that should be taken so leniently," user dailyvitajimin wrote. "if hes [sic] gonna be sensitive about being attacked, then maybe he shouldnt [sic] have attacked someone else in the first place."