- As several details in the Magical Girl Lyrical Nanoha franchise can only be found in supplementary materials like the Sound Stages and manga which the english speaking fanbase wasn't aware of for sometime, western fans took some 'facts' as a matter of course, such as Nanoha copying Fate's Bind spell (she didn't, Yuuno taught her how to do a Bind in the very first Sound Stage, which took place between Episodes 2 and 3) and Reinforce Zwei being the weakened form of the first Reinforce (she's not, she's a completely new Unison Device Hayate designed with the help of Mariel and Yuuno as mentioned in the last Sound Stage of A's). Most of these have died down ever since English-speaking fans learned about the supplementary materials and began translating them.
- Nanoha and Fate are generally considered to be romantically involved. While they are Platonic Life-Partners with a lot of Homoerotic Subtext, it's never made canon. Which can lead to some confusion when people go into the series having heard them described as "girlfriends". There's also that bit where Vivio considers both Nanoha and Fate her mothers muddying the waters. On the other hand, they're never actually confirmed not to be a couple, either. Their relationship is just ambiguous enough that they could either be lovers or very close friends. For that matter, despite what people may claim, none of the other possible pairings are ever actually confirmed either. Some of the characters have expressed interest, but none of them ever get a Relationship Upgrade, except for Chrono and Amy (which happened off-screen). It was later confirmed via Word of Gay.
- There are a few other persistent bits of fanon, such as the belief that Graham gave Hayate the Book of Darkness (on the basis that he said that if someone like her, with no friends or family, were sealed away with it, no one would have to mourn her), which is not true. The Book transported itself to Hayate, and Graham tracked it down.
- A lot of people seem to think that Subaru and Ginga were created by Scaglietti. They weren't. It was done partly using his research, but Scaglietti was not directly involved.
- And then there's the theory that the Wolkenritter were originally humans (or in Zafira's case, a familiar/guardian beast) who were absorbed by the Book of Darkness. Nothing of the sort has ever been stated in canon.
- An extension to the above is that Agito was originally created to be Signum's Unison Device.
- Another misconception about the Wolkenritter is that they had all their memories erased every time the Book of Darkness chose a new master. This is directly contradicted in the show, as they make references to how Hayate is different from their previous masters. It is stated that they lost some of their memories; but that only refers to their memories of the Book of Darkness going rampant. They also do not remember anything from before it became corrupted. Their memories of the intervals in between, however, are intact. This is stated outright in the commentary to the second movie.
- Vivio often calls Hayate, a close friend of both of her mothers, "Aunt Hayate" in fan fiction. So far, in canon, she hasn't called her anything other than "Commander Yagami", just like Hayate's subordinates, and even Nanoha and Fate themselves do while on duty.
- There are a number of misconceptions about how mage rank works. It is not simply a measurement of magical strength; as seen when Subaru and Teana take the exam for advancement, going up a rank involves passing what is essentially an obstacle course requiring the use of tactics, so a Weak, but Skilled mage can still qualify for a fairly high rank. However, Hayate's SS rank does denote her raw power, because she has a "Synthesis" rank, not a combat ranking like what most of the other characters have.
- Another misconception is that Hayate had no linker core before Reinforce merged with her. This is patently untrue, as Signum flat out says that the reason the Book harmed Hayate was because her linker core wasn't fully mature, and it's actually shown on screen for a couple seconds.
- It's commonly accepted that Graham is responsible for Lindy's habit of drinking her Japanese green tea British-style.
- Fans will often associate Nanoha as a lover of strawberry and cream based deserts and foods even though there is little to no evidence of this matter.
- There are quite a few fans, especially shippers, who believe that in order to differentiate herself from Alicia, Fate chose her own birthday and that the day she chose was the day when Nanoha and her swapped ribbons and became friends.
Fanon / Lyrical Nanoha