So there's this one series called Zero no Tsukaima. Most of you have probably heard of it, but for the rest of you, think of a Takahashi Couple attending Hogwarts and you've got the basic idea. Look here for a more in-depth explanation.
So you've got Louise and Saito, lead heroine and hero, if you can really call them that. Calling them a Takahashi Couple is kinda disingenuous because they aren't really much of a couple, Louise spends more of her time beating the crap out of Saito than Akane does with Ranma, and Saito's a real piece of work too, especially in the original light novels. They really are a match made in hell. Then a few months ago, a guy by the name of Gabriel Blessing started writing a fanfic called The Hill of Swords, where Louise summoned Emiya Shirou from Fate/Stay Night instead of Saito to be her familiar.
The fic caught a lot of attention on the Creative Writing boards over on SpaceBattles and sparked a lot of discussion in the fanfic recommendation thread. Shortly before it ended, yours truly got a rather crazy idea into his head: if Shirou can make Louise into an awesomesauce mage and a decent person to boot, what could other people do to her? The result is Breaking In Louise, which is about to hit 150 pages of discussion and has spawned several other ZnT threads and multiple fanfics starring familiars from all across the multiverse. We've got Asakura Ryouko, we've got Link, we've got Nono -- yes, the one from Diebuster! -- we've got Shirai Kuroko, we've got Alex Motherfrakking Mercer, and many others besides, along with original characters from series as far apart as Exalted, Whateley Academy, and the Forgotten Realms. Ideas have been put forth for hundreds more characters, ranging from Evangeline A.K. McDowell to Wodan Ymir to Takamachi Nanoha to (most recently) Tomoe Hotaru. It's been so busy that frankly I haven't had any time for you guys. But now I'm back, and I thought I'd bring the party with me.
So to those of you who are just hearing about The Hill of Swords, I highly recommend you look it up, it's a real piece of work (though there is a major sticking point with Shirou being majorly out of character, but that gets explained and justified as you go along). To those of you who have and who know a few things about Zero no Tsukaima, same question: who do you think would make a good familiar for Louise, and how would they change the setting?