a child is thrown into the underground,
they're so little, no more than 5. their father threw them- told them that they'd be going to meet their mom now.
they've never met their mom, but they're excited to! when the goat lady comes up to them, they ask, "are you my momma?". when she responds in confirmation, taking the tiny child into her arms, the child is happy. momma is much nicer than dad, and she's soft and looks like their plushies!
their soul is white - innocence. they're innocent to the wrongness around them, too young to understand this isn't what their father intended when he sent them to meet their mom. they're content, happy to spend their days with their momma. they don't need to leave, and though they miss their dad sometimes, they're a lot happier here with their mom.
is this innocent ignorance "right"? is it wrong for toriel to continue shielding them, both from the rest of the underground and the truth about their family, their birth mom? who knows