Adaptation, Part Two: "Ontogeny"
Mother said it was a duty. As a Phantomhive by blood and loyalty, Francis refused to let the family die. And, no matter what Lizzy would have wanted, she was of the bloodline as well and the second child of a Marquis who already had an heir.
To her credit, Mother had tried to break it to Elizabeth gently, building up to the announcement with talk of responsibility and lessons beyond the scope of those she'd had before. It was only after Lizzy had staunchly refused that Mother spoke of justice, of foul play; of how the Phantomhives deserved the first and had were responsible for sorting out the latter. To gain the resources that she needed, she would need to take on those responsibilities.
And if Elizabeth was to use her newfound resources to avenge the family that they rightfully belonged to, then it wasn't a betrayal, was it? She wasn't acting as if she was a replacement, but the final arrow shot by a bowman before he himself was felled.
A/N: To all of the beautiful people who reviewed: thank you! I love you all. And to the guest who mentioned chapter length: I'm trying, but thank you for pointing it out.
"Ontogeny:" of herself