Baby's height and build are nearly the same as the other Saja Boys members, with a slender frame and long limbs. He has fluffy turquoise hair styled in a mop top, a small round face, and large blue eyes. He also wears eye makeup and has painted nails. In demon form, most of his features remain the same, with notable changes including glowing yellow eyes, pale blue skin, clawed hands, and demonic markings. In his human form, Baby usually dresses in oversized sweaters, collared shirts, newsboy caps, and plain pants. In contrast, his outfit in the Demon Realm features a traditional black jeogori jacket layered under a jeonbok overcoat, secured with a sejodae sash, and topped with a gat. During the Saja Boys' performance of "Your Idol," he wears a gat and sochangui overcoat paired with modern clothing.Baby first appears in the Demon Realm alongside Jinu during a meeting with Gwi-Ma, where Jinu proposes a new strategy to defeat the Demon Hunters. He proposes forming a rival K-pop boy band to undermine HUNTR/X, the current generation of hunters, by winning over fans’ devotion and weakening the Honmoon. This leads to the creation of the Saja Boys, with Baby as one of its members. In his next appearance, Baby is seen in human disguise alongside the other Saja Boys in an alleyway, where they run into the HUNTR/X members. Shortly after, he performs the song “Soda Pop” with the group in a town square. Later, the Saja Boys compete on a variety show in a hot sauce drinking contest. Baby wins the competition, drinking the sauce with ease and finishing with the phrase, "goo goo ga ga." After the show, he is shown with the Saja Boys at a men’s bathhouse, where they trick HUNTR/X into fighting water demons. After gaining popularity, the Saja Boys return to the Demon Realm to report their progress to Gwi-Ma. Baby is shown posing in his idol persona before transforming into his demon form, looking visibly exhausted. In later appearances, he is seen with the group as they receive awards from various Korean music programs. He is later shown wearing a sleeping bag shortly before the Saja Boys interrupt a HUNTR/X fansign. During the event, the two groups share a table, with Baby sitting between Zoey and Jinu. Unlike the other Saja Boys, Baby keeps himself occupied by drinking water. Although he appears touched by the flower bouquets given by fans, he discards them in a trash bin immediately after leaving the venue. In his final appearances, Baby is seen backstage with the Saja Boys at the International Idol Awards. He later performs with the group at their Namsan Tower concert, singing "Your Idol" in demon form. When Rumi interrupts the show to reunite with HUNTR/X, Baby is shown flying toward the girls and engaging in a brief fight with Zoey. After Jinu sacrifices himself to empower Rumi in the battle against Gwi-Ma, Baby looks shocked. His fate is not explicitly shown, leaving his final status unknown

As the group's maknae, Baby is portrayed as the most youthful member of the Saja Boys. On stage, Baby will play up the cute persona by using childish props, pouting, and making playful gestures. Additionally, he is seen to be competitive, notably winning the hot sauce challenge on the variety show Play Games With Us. However, unless he's interacting with fans, he puts on a bored, uninterested mask and has a nonchalant façade. Nevertheless, he shows genuine shock when Jinu sacrifices himself for Rumi.