Mystery

This is the song soda pop by the Saja boys. Saja boy members: Mystery, Jinu, Romance, Abby, and Baby Saja.

Intro (all)

Hey, hey
Hey, hey
Hey

Jinu sings: Don't want you, need you
Yeah, I need you to fill me up
마시고 마셔 봐도
성에 차지 않아
Got a feeling that, oh, yeah (Yeah)
You could be everything that
That I need (Need), taste so sweet (Sweet)
Every sip makes me want more, yeah

Mystery sings: looking like snacks

Romance sings: ‘cause you got it like that.

Abby sings: Take a big bite, what another bite, yeah. 너의 모든 걸 난 원해, 원해, 원해 너 말곤 모두 뻔해, 뻔해, 뻔해

Mystery sings: when you’re in my arms, I hold you so tight. (So tight). Can’t let you go, no, no, not tonight.

Jinu, romance sings: 지금 당장 날 봐 시간 없잖아
넌 내꺼야 이미 알고 있잖아
'Cause I need you to need me
I'm empty, you feed me so refreshing

Baby Saja sings: my little soda pop

All sing: You're all I can think of
Every drop I drink up
You're my soda pop
My little soda pop
Cool me down, you're so hot
Pour me up, I won't stop
You're my soda pop
My little soda pop
My little soda pop.

Baby Saja raps: Uh, make me wanna flip the top
한 모금에 you hit the spot
Every little drip and drop, fizz and pop, ah 소름 돋아 it's gettin' hot

Abby sings:

Yes, I'm sippin' when it's drippin' now
It's done? I need a second round
And pour a lot and don't you stop
'Til my soda pop fizzles out

Mystery, Abby, and romance sing:

꿈 속에 그려왔던 너
난 절대 놓칠 수 없어
널 원해 꼭
I waited so long for a taste of soda
So, the wait is over, baby
Come and fill me up
Just can't get enough
Oh

All sing: You're all I can think of
Every drop I drink up
You're my soda pop
My little soda pop (Yeah, yeah)
Cool me down, you're so hot
Pour me up, I won't stop (Oh, oh)
You're my soda pop
My little soda pop

Jinu sings:

Ooh, ooh
Ooh, ooh
You're my soda pop
Gotta drink every drop

Shapeshifting
Singing skills
Charisma
Pyrokinesis
Demonic physiology
Demonic magic
High intelligence

Mystery seems to fashion himself as someone who is always shy and quiet, with many of his poses simulating embarrassment. He notably emotes the least of the Boys, likely due to his eyes being covered. This is all used by him to make his fans trust him.
What personality he does show depicts him as mischievous and sly like the rest of the Saja Boys, especially when it comes to taunting Huntrix. He is implied to be more aggressive than the other Saja Boys, seeing as during the Signing Event, he started barking incoherently at a fan for no particular reason and he’s the first one to attack Zoey when the plan goes awry. But he and the rest of the Saja boys change their minds and helped Huntrix defeat Gwi-Ma.

In both his demon and human forms, Mystery is depicted with his hair styled in a way to where it covers half his face. As a result, his mouth is the only visible facial feature of his.
His human forms shows him in a yellow turtleneck, as well as yellow armwarmers and a blue vest with his hair being light blueish purple.
His demon form depicts him in a black attire, his hair being more dark blueish purple, and wearing a dark hat. His skin is more pale and covered in markings and has claws and fangs like the rest of the boys. Is Korean. Has a Korean accent. Speaks English and Korean fluently. Age is unknown but he’s 18+.

Unknown. Was a human who made a pact with Gwi-Ma and accidentally become a demon. He was sent with Jinu, Abby, romance, and Baby Saja to the mortal realm by Gwi-Ma to become a demon boy band called the Saja boys. They worked to destroy Huntrix, the new gen demon hunters. Huntrix is made up of Rumi, Zoey, and Mira. Mystery likes Zoey. Later worked to help Huntrix destroy Gwi-Ma. Him and the rest of the Saja boys are now free in the mortal realm.