The Saja Boys (Korean: 사자 보이즈 RR: Saja Boijeu) are the secondary antagonists in the film KPop Demon Hunters. They were a five-member boy group composed of Mystery, Abby, Jinu, Baby, and Romance. Secretly a band of demons in disguise, the group was formed to weaken HUNTR/X's fanbase and destroy the Honmoon, allowing Gwi-Ma to ascend to the surface world.

After Gwi-Ma’s demons continuously fail to eliminate the current generation of demon hunters, Jinu boldy approaches the king and proposes a new strategy: rather than fighting hopeless battles, they should form a rival boy band to draw fans away, thereby undermining HUNTR/X and the Honmoon's strength. Although initially skeptical, Gwi-Ma ultimately approves the idea and allow them to proceed.

Currently, it is unknown how Jinu met the other members, how he convinced them to join him, and how long they trained for.

Chronology

Disguised as K-pop idols, the Saja Boys bypass the Honmoon's barrier and debut with a street performance of "Soda Pop", later going viral after appearing on the variety show Play Games With Us. Their sudden fame draws the attention of HUNTR/X, who confront them at a bathhouse but are ambushed by water demons.

During the encounter, Jinu discovers that Rumi has demon patterns, a secret unknown to Mira and Zoey. After the fight, he is pulled into the demon world to report to Gwi-Ma, who admits he has no control over Rumi despite her markings. Jinu then vows to exploit Rumi’s hidden shame for the group's advantage.

As the Saja Boys’ popularity soars, they secure a place in the International Idol Awards, part of a scheme to harvest souls from a massive audience. Meanwhile, Jinu grows closer to Rumi and agrees to pull the Saja Boys from the competition so HUNTR/X can seal the Golden Honmoon, securing his freedom on the surface world. But when Gwi-Ma uncovers his plan of betrayal, he mercilessly forces Jinu back into submission.

Reunited under Gwi-Ma's command, Jinu and the Saja Boys devise a trap by separating Mira and Zoey from Rumi at the Idol Awards, and sending demons disguised as them to confront her on stage. During the hijacking, they twist the song "Takedown" against her, exposing her half-demon heritage to the world. Staggered by Mira and Zoey’s reactions, Rumi flees in humiliation.

With the Honmoon shattered and HUNTR/X split, the Saja Boys direct the masses to Namsan Tower for a midnight performance. At the tower, they captivate the crowd with a new song, "Your Idol", including Mira and Zoey. As the performance doubles as a ritual to summon Gwi-Ma, he begins to manifest, growing in size.

But Rumi returns by the end of their performance, having embraced her half-demon heritage, and counters with a heartfelt new song, "What It Sounds Like." Immune to his influence through her human blood, she breaks Gwi-Ma’s hold on Mira and Zoey, who reunite with her in acceptance. Together, they reform HUNTR/X and begin to break the Saja Boys' spell over the crowd.

Enraged by the song’s power, Gwi-Ma orders his demons and the Saja Boys to stop HUNTR/X. When they easily cut through his forces, Gwi-Ma absorbs the remaining demons and prepares to kill Rumi directly. At that moment, Jinu betrays Gwi-Ma by taking the blow meant for Rumi, using the last of his strength to transfer his soul to her. This empowers Rumi to summon a larger sword capable of injuring Gwi-Ma.

As the situation worsens for Gwi-Ma, the Saja Boys desperately attempt to stop HUNTR/X but are quickly overpowered by Mira and Zoey. The crowd’s support empowers the song to such an extent that a new Honmoon is formed, banishing Gwi-Ma and his remaining demons back to the demon world.

After the Namsan Tower incident, Saja Boys merchandise is shown discarded in a trash bin, implying that the group lost popularity after abruptly ceasing activities, or when the public discovered their true nature.