A Fairy Amongst Us
Harry Potter x Fairy Tail
Fem! Harry
Harry is Evergreen
Harry (Evergreen) xElfman
Fairy! Harry
De-aged! Harry
2 years younger than canon! Evergreen (that would make her 18, the same as Elfman)
-Elfman joins guild when he is 12, he is 18 in canon
-It isn't stated when Evergreen joins, just that it was when she was a child
After the war Harry's health declines greatly, but no one is really left to make sure she stays healthy. She remains in one of her family estates, most likely Potter Manner or something.
Then one day she just has enough and goes to Gringotts, where the goblins lead her to their 'king' Ragnok. Who upon seeing her appearance (Which is that of a 19-20 something young which that looks much too old and frail for her age) gives her an offer, she really can't refuse. (Harry has also made things up to the goblins by this point).
He offers her a new start somewhere, where no one will know her but the goblins that live there. Harry agrees seeing on benefits.
So she makes a will, stating that upon her passing, which one of her ancestral homes shall become an orphanage for magical children, and another will become a school for pre-Hogwarts or other magical schools, that will also teach mundane studies. And finally a third house will become a safe haven for magical creatures and supply them with any necessary treatment and shelter they might need. She also states that is Luna Lovegood (one of her last remaining friends) would oversee the three places, then she would be most happy and relieved. She also leaves behind enough money for any future magical orphans tuition for school (either Magical or mundane). The goblins as stated in her Will, will be overseeing the projects.
They then take her to a special chamber that only they know of, where they have her take potions to hopefully restore her health, and the expand her knowledge of Earth, and then give her even more knowledge of Earthland, and it's counterpart Edolas. They then somehow make a clone of her body, which they put into her home that 'dies', which sets off her Will. (Luna obviously knows that Harry isn't actually dead, but has been freed). Then after Harry's body has settled in the new knowledge and regained some strength they de-age her, turning her into a two year old. Then for the next '2-3 years', she practiced Earthland magic, mainly Fairy-magic, and controlling her eyes, which she inherited from the basilisk venom - called Stone Eyes, she also learns Light-magic. The goblins during this time has sent word ahead to Earthland to a friend that lives there, who has agreed to escort Harry and to look after her when she leaves their village. This friend is named Makarov. The goblins have also been moving/transferring Harry's wealth to a vault in the goblin village in Earthland, so her money, heirlooms, books and other belongings are being taken and hidden away from the Earth magicals, all but the buildings and some portraits and whatever money is left for the school/orphanage/clinic is transferred. So Harry now physically the age of a 5 year old has enough strength to go 'across', she does so with a goblin escort. She is welcomed warmly by the village, who teach her even more things about her new home and how to survive in it, while they wait for Makarov to arrive. It takes maybe half a year for the news to reach Makarov, and for him to arrive at the village to meet the young fairy.
Upon meeting and getting to know Harry, who no longer wishes to be called such, and has been bequeathed with the new name Evergreen by Makarov (evergreen stands for renewal and vitality, along with being strong and steady). Harry/Evergreen loves her new name and hugs Makarov and proceeds to call him Uncle and sometimes Grandfather, for that is how he treats her. Makarov decides to invite her to his guild, but first wishes for her to visit Tenrou Island, the home of fairies and to meet Mavis, Evergreen quickly agrees, having never really met another fairy before. They bid the goblins goodbye promising to visit at least once a year if possible. The two head to Tenrou where upon arrival Ever's magic reacts to the island and sends her straight to Mavis' grave, where Mavis' ghost proceeds to greet her, claiming Ever as her 'child' (descendent), Makarov is surprised but makes no comment allowing Mavis to talk and explain things to the two of them. Mavis then proceeds to teach and instruct Ever in the three ancient Fairy spells, that the guild is known for, telling Makarov that even though she is physically a child her mind and magic are well passed her years and that she can handle it. Mavis also states that he can trust Ever with his secrets, she will never judge him, for he is giving her a home and a family, things that Ever has always wanted. It takes Ever about a week to learn the three magics (though not to perfection). Mavis claims she is proud of her and gives her an old journal to study and learn from in the coming years (it's a book about Earthland fairies and their magics), Ever enthusiastically agrees and happily goes with Makarov to Magnolia to meet the guild, to meet her new family.
The years go by with Evergreen climbing the ranks, she also befriends both Freed and Bixlow sometime during this time and Laxus (which was a request from Makarov). The four of them become the Thunder-God Tribe and its leader, and go on many adventures overtime.
Eventually canon events occur including the Battle of Fairy Tail, which Ever had warmed Makarov about due to being so conflicted about it, both not wanting to lose her friends (who have become like brothers to her), nor her guild mates (her family). So she confers with Makarov and tells him of Laxus' plan all the while crying. Makarov comforts her and forgives her. Events then once more proceed like canon. Eventually we get to the part where Elfman and she gets 'together' after much teasing being done to them.