Slytherin
1a. Iris Potter knows that the world is out for her twin. She also knows where his biggest problems are going to come from. Well, she's been further behind enemy lines before, and this is the best way for her to make a difference. She looks across the hall, at her naïve, happy brother, and braces herself.
You will do great things in SLYTHERIN, The Sorting Hat whispers in her mind and shouts to the world.
I'm counting on it.
1b. For all that Slytherin is supposed to be the house of ambition and cunning, the latter trait has been sorely diluted by the glory-seekers among certain factions coveting the prestige of Lord Voldemort's own house. It is disappointingly easy to manipulate the house of manipulators.
Even Snape, master manipulator and triple-spy for the two most wily, powerful men in Wizarding Britain, has one glaringly obvious weakness. Lily Potter's daughter looks like her mother except for the eyes, not that that matters when said eyes are filled with tears. She learns to play Snape like, well, not a fiddle; she's never been very musical, but something like Kankuro plays with his puppets. No one seems to realize the foundation she is laying. The game is set, and no one here comes close to matching Shikamaru's shogi skills.
2a. Iris handles Dobby – she has a great understanding of the Malfoys after a year of living with one of them. Dobby stops interfering. No one is charged for underage magic use, no one puts bars on their window, and no one stops them from getting to school unscathed.
2b. Lockhart is an incompetent fool who is wasting her time. He gets removed from his teaching position when his scandalous lies are revealed a few weeks into term. It turns out that Blaise Zabini's maternal aunt fights the dark natural magicks of the Congo. She submits her name to take over for the term when Blaise writes her about their troubles and mentions the book deal his esteemed friend Ms. Potter is willing to sponsor.
2c. Their fierce new professor confiscates Ginny's diary, and delivers the dark artifact to Dumbledore. She's a also good teacher and an interesting woman to read about. Iris makes back the loan on her cut of the book in the first six months of sales.
3a. Iris is back in Tsukiyomi. She screams and screams and nothing changes but the specific images of the black on red. The next thing she knows is the after taste of hot chocolate in her mouth. Apparently, that's the preferred magical remedy for this sort of thing. She finds out that she reacted so poorly to the Dementors, that she's been out for a week.
When she campaigns to have them removed from the school, the public is on her side. The ministry has no choice but to fold when the Dementors storm the quidditch pitch and almost kill her brother.
3b. Iris works harder to learn the Patronus than she has for almost anything else in this life. She thinks of a future where Harry's safe and happy, or a past where Naruto's Konoha was peaceful and happy, and an armor-clad Stag bursts from her wand. Heijomaru's form confirms that deer were the right summons for her after all.
3c. Harry shares the Marauders map with her and she spends all year trying to make a copy. She stares at the thing so much that she happens to be looking when Sirius, Pettigrew and the Golden Trio head under the Whomping Willow. She sends Professor Sprout down to the Willow with concerns about its odd behavior, and calls in a favor owed to get a 5th year Slytherin boy to stall Snape. Pettigrew stills gets away, but no one gets executed or Kissed. She grudgingly accepts this outcome.
4a. She senses Crouch Junior under the cloak. She must have been influenced by the Gryffindor's she'd been living with all Summer, because she brashly pulls off the cloak in the middle of the Minister's Box, and a fight ensues. Wands are no match for an elf protecting her master, though, and he gets away. At least they get the real Mad-Eye Moody for a professor.
4b. Karkaroff must be trying to redeem himself, because Harry's name still comes out of the Goblet. Iris isn't even all that surprised, any more. Lucky Sevens indeed. She teaches him earth walking to deal with the dragon. Water walking and tracking tags likewise cut down his time under the lake. She wakes up in his arms in cold water, to Harry winning his second challenge in a row. Between his head start and the things Iris has taught him over the years, Harry beats Cedric to the cup in the Third Task by miles, and gets portkeyed away alone. He comes back alive, but now Voldemort is too.
5a. The Order of the Phoenix won't let them into meetings, but Fred and George's extendable ears are the brilliant magic she expects. Iris rolls her eyes at some of the things they're speculating about. Mostly, she's glad for this world's kid gloves when it comes to child rearing and war. Sometimes, though, she longs for Konoha's pragmatism. When the meeting's over, she doesn't pretend, like the others, she didn't hear anything. She marches straight up to Mad Eye Moody (the most practical adult in this bunch) and hands him a piece of parchment with her notes from the meeting.
"What's this?"
"A list of answers to some of the questions we heard you asking."
"What?"
"You do realize I live with most of those people's kids, right? People talk."
That's how, at fourteen, she becomes the youngest spy ever against Voldemort.
5b. Over the course of the school year, Umbridge gains power and starts the inquisitorial squad. Iris deliberately cedes the powerful positions to Malfoy and his cronies. The smarter Slytherins catch on to what this means.
I'm not in charge of Umbrige's regime because I don't want to be. Because she is the losing side. Not because I couldn't be.
She's right. By the end of the year, Umbridge falls. Between that and his father's humiliation, Malfoy falls too. Slytherin belongs to her.
6a. Slughorn is more than just an opportunity. He's a downright inspiration. Iris knows they'll do great things together.
6b. She didn't know Harry and Dumbledore were leaving for the cave until Death Eaters pull her from her bed. Apparently, one of the Death Eater's kids let them in. Most of her housemates don't like one of their own being attacked. Between the other students' rebellion and a few well-placed touch blasts, she gets free, and the Death Eaters are beaten back. She rallies her "loyal" Slytherins, and anyone that sat out or joined the death eaters in the fight is stunned and put under guard. Under Iris' careful direction, the older kids set up traps and a watch shift to protect the younger ones.
When Slughorn comes to break the news of what happened the previous night, he clearly didn't expect to step into a battleground, bloody corpses and all.
When the rest of the school hears that Slytherin was besieged last night, that they had the most injuries and took down the most Death Eaters, and that most of them categorically aligned themselves against Voldemort, opinions begin to change.
6c. Most of the Slytherin house stands proudly at Dumbledore's funeral. It's been a long time since the other houses have truly accepted Slytherin, but they have shown their true strength now. Hogwarts battle lines are drawn between Death Eaters and not, rather than between houses.
7a. A dozen extra wands on their side and a number of hesitating Death Eaters on the other side makes more of a difference in the Battle for Hogwarts than you might expect.
7b. When it's all over, when Voldemort's dead and their dead are being honored, Iris finally gets the full story. Fear and anger blaze in her, briefly, at his secrets and lies but she knows she's a hypocrite.
Dumbledore was in Gryffindor because he believed in his own righteousness, but he sure would have made a great Slytherin.
*Iris- A flower, like Lily or Petunia. Symbolizes eloquence, and depending on the color, can also mean passion, wisdom, or faith. Species are found in nearly all parts of the world, including Japan, America, and England. Not related to deer, as far as I know.
