To be fair, that is like, implied since the very beginning, the author, the system and the others keeping Yi-young away from her world may cherish her but more as a doll or an idol from an YouTube channel, a character.
They don't see her as a human being with emotions or her own concerns, they just desire entertainment, if they really cared, they would've returned her to Earth when she accomplished the first scenario.
Another possibility is the theory that I had in the back of my mind being right however:
perhaps Yi-Young cannot be returned back to Earth, she died and got reincarnated, but perhaps they cannot revive her on Earth due to being outside their domain. Or the time flow went way past ahead on Earth, but the administrators are too cowards to tell her the truth.
If I'm correct Water-sis is Goddess Ganga, as in the personification of river Ganges and worshipped in hinduism as the Goddess of purity and forgiveness. She rides a crocodile-like creature as seen in the illustration.
Edit: my bad posted this before reading the entire chapter. Still though, Varuna is supposed to be a guy. But then again hindu deities sometimes appear in different forms.