Eliza is the central figure in one of the two major plots, which she sets in motion by running away. She is the first example of a mother whose young child is sold, and she turns out — ironically — to be the only example of a child returned almost miraculously to a mother. She has what is probably the most famous scene in American literature when she leaps across the breaking ice on the Ohio; and she has a sweetly funny line when she disguises herself as a man and offers to "stamp and look saucy" in order to help with the illusion (George discourages this). But apart from these few things, and despite Stowe's assurances that her character was drawn from life, Eliza is a stock character, an abstraction — just another pretty face. Partly, this may have been to ensure that to white readers could identify with a young woman who looked and behaved in fashionable ways; partly, no doubt, Eliza's character as a conventionally "good" young woman was simply less interesting to Stowe than someone, for example, like Marie St. Clare.
But one possible reason that there seems to be little to say about Eliza, beyond the fact that she is conventionally good, is that she was drawn from life. Cassy tells Tom that Eliza was a timid, obedient child. Traumatized early by being sold away from her mother as a slave, then taken to Kentucky and given to young Mrs. Shelby, Eliza no doubt transferred her affection as much as possible to her new mistress and did what she could to please this very conventional and kind but passionless woman, becoming as much like Mrs. Shelby as possible.