This starts after Dumbledore explains everything at the end of the book. It's not important to the plot, but answers some questions. If you have any that aren't answered, please ask in the comments. Enjoy :)
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Harry's POV
Harry started to leave, but paused.
"But... if I have some of Voldemort's powers... and that's how I can speak Parseltongue then how can Delilah? She doesn't have a scar."
"This is only a guess," Dumbledore said. "But twins have a special connection, just like twin wand cores. Your sister could have unknowingly used that connection to learn Parseltongue."
"So... does she need to stay at the Dursleys' once every year too? This summer she's planning to go to the Malfoy's."
Dumbledore frowned.
"It would be best for her to have the extra protection. Voldemort may try to go after her to get to you."
"Should I try and convince her to stay?"
He nodded.
"That would be for the best, but wait for her to reach out to you. She surely will."
"Ok, I'll try."
"I suspect she will stay if you ask her to."
"But why? I've barely seen or talked to her all year."
Dumbledore smiled softly.
"You are her twin brother, you will always have a connection, even if you ignore it for a while."
Harry nodded, then paused.
"Wait, so if she could learn Parseltongue from me, could we learn other things from each other?"
"Potentially, if you grow your bond over the summer. It would be an interesting project to keep you busy while you wait to leave Privet Drive. I'm intrigued to see how it would work out."
"Ok, I'll try. Um, thanks for finally telling me everything. Bye?" He had not meant to have the last statement sound like a question, but Dumbledore didn't question it, instead nodding his approval.
Harry left the room, his head spinning.
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Thanks for reading this, I know it's not super long. If you have any relevant questions that didn't get addressed in this, please ask in the comments. -Moony 🌙