[Thanks to ThisMightEndBadly for your review and Follow. Nessarose will be three years younger than Elphaba, and Shell will be seven years younger than Elphaba. I don't know their exact ages, so I just gave an estimate.]
"Of course, the blood contains thousands upon thousands of blood cells, both white and red. The red blood cells are what give blood its colour, predictably. Can anyone tell me where the nutrients are carried in the blood?" Lecturing steadily, Elphaba paced from one end of the battered blackboard to the other, tapping her spindly fingers upon diagrams and flow charts to emphasise her points. Wrapped up in the lesson, no one noticed a small woman shuffle awkwardly into the room with a practiced gait of careful balance. As a result, everyone jumped a mile when they heard a smooth, oiled voice answer their professor's question for them.
"Don't tell me, I know this. Oh, I learnt this so recently! Could it be... the plasma, Fabala?"
The woman's head tipped and her coffee brown eyes lifted upwards towards the heavens, as if thinking deeply and ponderously. She gave the perfect illusion of holiness, but not wholeness. For this girl was armless.
"Nessa? What are you doing here?" demanded Elphaba, wanting to know who had let her Nessarose wander without a steady arm to support her if needs be. She rushed to Nessa, gently guiding her by the waist and shoulder, knowing instinctively which areas to push that wouldn't hurt her pretty Nessarose.
"Class, I need to convene with my sister. Amuse yourselves quietly for a few clock-turns. I'll be back soon." Elphaba threw the instruction over her shoulder, still focusing on supporting Nessa.
Shutting the door behind her, Elphaba turned to her sister, who had sat down and arranged herself aristocratically, thin ankles crossed in the proper fashion for company.
"Nessa, my Nessa, why are you here? Are you alone? Did Father let you wander Shiz on your own-" The onslaught of worried questions began to spill forth, but Nessa simply gave her sister the look. This was an expression patented for when Elphaba got too fussy. Elphaba shut her mouth at once. Look how quickly I am submitting to her whims, Elphaba thought. Old habits truly do die hard.
"First and foremost, I am not alone. Nanny is with me."
"And where is Nanny?"
"Waiting in the carriage for me to come back with you."
"She let you walk in unchaperoned?" Disbelief tainted Elphaba's voice as her eyebrows lifted.
"Yes, she did. I must savour the small moments of my own independence." Nessa's chin lifted. She smiled delicately and motioned for Elphaba to sit down with a nod of her head towards the bench. The eldest Thropp shook her head. Nessa sighed heavily. Reluctantly, Elphaba perched on the very edge of the seat, simply to appease her baby sister.
"Why are you here, Nessie? Can't you see I'm teaching?"
"Yes, Fabala, but Father wants you home."
"And Father couldn't possible come to tell me this himself, my pretty?"
"Father is... preoccupied."
"With?" prompted Elphaba.
"Shell." Nessa answered shortly.
"Shell. Father is preoccupied with Shell, who is sixteen years old and perfectly capable of caring for himself." Elphaba stated, her voice monotone. She clearly didn't believe Nessa.
"You don't understand, Fabala. Shell only got worse after you told us you weren't coming home after Shiz. When you said you were staying to teach, Shell just lost every will to behave."
"I didn't realize I had quite that much influence on our baby brother."
"Stop it, Fabala. You know how he looks up to you. His never-weak big sister, who went to the best University in Oz."
"I seem to remember the words 'I probably won't miss you' escaping his lips."
"Arrant nonsense. He was just trying to be manly. He locked himself in his room after you left. Then his behavior began to worsen. The Unnamed God knows he was a mischievous boy from birth, but he just... gave up trying." Elphaba had missed Shell, but he wasn't her child, only her brother.
"Father is his parent, as well as ours, my pretty. Surely he should deal with what the Unnamed God sent him?" Nessa frowned disapprovingly at her sister for the gentle jab against her religion.
"You were his mother when he had none, Fabala. After Mother died, you were so strong. My earliest memory is of you rocking Shell in his swaddling clothes and singing a hymn to quiet him. It's my favourite memory too." The emotional guilt was carefully designed to press at Elphaba's weakness; her family, especially her siblings.
"I-" Elphaba started uncertainly, reconsidering. If Shell was as bad as Nessa said, shouldn't she go home? It was then she saw the triumph in her sister's eyes. And she realized.
Nessa wanted her sister back. Shell wanted his sister back. To care for them both, as she had always done. Father wanted his daughter back to care for her siblings, while he could gallivant after another one of his precious lost causes, shirking his paternal responsibilities. Her resolve strengthened, like hardening Glikkun iron.
"No."
"No, Fabala?" Now Nessa was uncertain. Victory had been so close.
"I'm not coming home to do Father's job for him. I'm sorry, my pretty, but I have my own life to live." She thought of her job, her apartment, her students. Don't go there, Elphaba, she warned herself silently, when Fiyero's face crept into her head. Nessa, previously a pining kitten, grew into a growling tiger.
"No? No?! You would see me and Shell starve and flounder without you?!" She stood up unsteadily, shaking with rage.
"Father is called that for a reason, Nessa! He is a parent, so he should parent." Elphaba tried to reason with her sister.
"You know he had duties outside of us, Fabala! Holy duties!" Nessa's religious zeal began to preach. Loudly. Within earshot of Elphaba's class.
"Nessa, my pretty-" Elphaba pleaded, reaching for her shoulder to hold and calm her.
"Don't touch me, Elphaba! Any wretched creature who would abandon her family in their hour of need should not be touched by a blessed hand!" Elphaba stopped, struck by her sister's harshness.
"I am not wicked, my pretty. Nor am I cursed."
"You are to me." Nessa hissed, no room for remorse in her voice. "Goodbye, Elphaba. I hope you enjoy your life."
Nessarose Thropp, dearest sister to Elphaba Thropp, stalked away as best her armless body would allow, sparing not a single glance backwards.
Elphaba collapsed heavily on the bench, feeling her bones rattle with the force of her fall but not caring one whit. She put her head in her hands. Her shoulders began to shake.