The girl, only known as Lia, is but one of many unfortunate victims who came across the water slime Aquania to be used as its host. So far none had survived being host to it but this girl looks to be one who has survived the longest thus far, but one can only hold their breath for so long before falling prey to the need to breathe which the slime loves to refuse. However, it seems like Aquania might have taken a liking to Lia, which might explain how she's survived for so long.