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이지현 as Romi (voice) |
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조경이 as Heartsping (voice) |
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최낙윤 as Heart King / Monster Truthping (voice) |
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여민정 as Belita / Girl (voice) |
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홍소영 as Stella (voice) |
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홍범기 as Dr. Monziu / General Teenieping (voice) |
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김하영 as Marie (voice) |
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류승곤 as Liam / Butler (voice) |
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조현정 as Truthping (voice) |
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김은아 as Happying / Young Liam / Girl's Mom (voice) |
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장예나 as Lalaping / Maid / Stickping (voice) |
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Um Sang-hyun as Mr. Bus Stop / Freezeping (voice) |
| Directing | 김수훈 | Director |
| Production | 민슬기 | Producer |
| Production | Song Mi-seon | Producer |
| Production | 신현덕 | Producer |
| Production | 김수훈 | Executive Producer |
| Sound | Jo Seong-hee | Sound |
| Sound | 윈터 | Theme Song Performance |
| Visual Effects | Kim Dae-yeol | VFX Supervisor |
| Writing | Ryota Yamaguchi | Original Story |
| Visual Effects | Kim Young-jin | Animation Director |
| Writing | Naruhisa Arakawa | Writer |
| Sound | Kim Tae-ho | Music |
| Production | 강병채 | Producer |
| Writing | Jo Yeong-gwang | Storyboard |
| Art | Im Ji-eun | Production Design |
| Art | Kim Yu-jin | Production Design |
| Art | Seo Bo-guk | Art Direction |
