My 6th grade Mary Sue OC goes to Hogwarts

Nixie Prepares Harry To Defeat God

Nixie lead Harry through the mansion in order for them to finally review. It was just before he was due to get his Hogwarts letter, and Nixie did her best to explain to Harry all of the history that he would need in order to know who to trust. She, as his only living family and the most powerful witch, would probably be his only saving grace here. Nixie, her parents, and the elves did their best to try getting him a happy life and proper education.

"Alright, so, lastly, proper titles- Ma'am, Sir, for general positions of authority such as teaching, Lord, Lady, for married head couples, Head, for those like you, which are pretty rare, Heir, for future Lords or Ladies, don't refer to someone by their first name unless told."

"Yep! And that concludes our speed run of politics. Now, try casting some general charms." 

Nixie admired how her cousin took to casting spells. Although it wasn't as quickly as she took to them, nor as powerful, she knew that if it were not for her, he would most likely be the most powerful wizard in terms of potential, but not actual practicality. Her kidnapping of Harry lead to him being much, much healthier, more happy, and he no longer had to hide his intelligence. 

He wasn't quite as smart as she was, but it made since, considering that she was a prodigy and was taught for years in advance. He was clever if anything, his quips were excellent and she honed that into more political skills for him. His magic took to his family gifts and death more than anything, which Nixie was glad for, as his power over death could lead to her being able to find more ways to duplicate his immortality, and for her to hopefully become more well known throughout the medical field. 

Leading Harry, she was able to take him beyond what the teachers were allowed to teach. When they dueled, Nixie would purposefully limit her casting so that Harry could get a chance to learn, and for how they could team up to decimate their enemies. 

"Harry, remember that dodging and blocking is even more important than attacking. It's all about reading your opponent, really. With wandless and silent casting, you become a much more difficult person to fight, since your opponents can't predict what you're trying to do. Attack when you think you have broken your opponent's predictions through your maneuvering." Nixie remembered as she reflected on their initial lessons.

Nixie looked as Shrek appeared. 

"Mistress, the owl carrying Mr. Hadrian's owl is nearing."

"Thank you, Shrek, have fun as you terrorize the local children."

Shrek bowed as he popped off. 

"So, Harry, you want to watch me play with Dumbledore?" Nixie looked at Harry as he stopped muttering spells.

"Of course!" Harry sat down on a couch as Nixie summoned a crystal ball to show what him what was going to happen. 

"I'll be back in a couple of hours, then. Our link should be fine, just remind me to not overdo it too much."

"Yep, Nix. Raise some hell." 

Nixie apparated into the wards of Privet Drive. Harry's golem was acting as he normally would, as it went through the motions of getting the mail. Nixie smiled as she froze time. Undoing the spells that caused the golem, she set up a copy of the magic of the golem for herself and reorganized her mind to make it look past Harry's.

Manipulating the Dursley's minds to alter the needed memories was successful. Nixie looked at her new body and felt the old magic, feeling more like she could successfully con Dumbledore. 

Writing a reply took a few minutes, and she was able to find the owl who gave the letter fairly quickly. Waiting for a knock on the door as the Dursleys successfully forgot "Harry" was even there didn't take long, and she knew exactly who had shown up.