Yeo Miseng (여미생, Yeo Misaeng; or "Yuh Meesaeng") is a Regular currently inside the Hell Express en route to the 43rd Floor. She climbs the Tower in search of her parents. Yeo Goseng and Miseng come from the same family and are of the same generation level. This is because they share the same surname "Yeo"(여) and they share the same generation name "Seng"(생): 미생(MiSeng) and 고생(GoSeng). They are probably cousins. SIU has confirmed they're not sisters, insinuating they're most likely from the same family and know each other very well (again, they are probably cousins).