The larvae don’t have another parent; they’re all parthenogenetic clones of Serick. She doesn’t mind if you think they’re disgusting. She actually agrees with you. 

Despite being sentient, cromnari (Serick’s species) are actually r-selectors. They find their own offspring disgusting so it’s no big deal for them to let them go and fend for themselves. Serick will look after her revolting larvae for a day after they hatch to make sure they’re fed and rested, then she’ll take them to the countryside and never knowingly see them again. Cromnari don’t consider that sad; it’s just how they do things.

'Don't they feel bad about abandoning defenceless larvae to the wilderness?' Oh, cromnari larvae are far from defenceless. If you see a pack of them, best give them a wide berth.