Cast
이지현
Romi (voice)
조경이
Heartsping (voice)
최낙윤
Heart King / Monster Trouping (voice)
여민정
Belita / Girl (voice)
Hong So-young
Stella (voice)
홍범기
Dr. Monziu / General Teenieping (voice)
Kim Ha-yeong
Marie (voice)
Ryu Seung-gone
Liam / Butler (voice)
조현정
Trouping (voice)
김은아
Happying / Young Liam / Girl's Mom (voice)
Jang Ye-na
Lalaping / Maid / Stickping (voice)
