Preferential Treatment
This recurring royal tool deals effective damage to armor and cavalry units, despite what its description may tell you.
Rapier
In addition to extra Trial Maps, connecting a copy of Binding Blade, Blazing Sword, or Sacred Stones to Path of Radiance unlocks this mode.
Art Gallery
Karel (FE6)
In the original Thracia english patch, Kempf's dialogue when you fall for his trap contained an out-of-place reference to this seminal fan work.
Yu-Gi-Oh! The Abridged Series
Caeda received this gift in the DS remakes to make up for losing access to Jagen's Silver Lance, but it was absolutely a winning trade.
Wing Spear
Despite being a mainstay class in the series since Gaiden, Shadow Dragon locked this class behind having a Wi-Fi connection.
Falcon Knight
Though some units in Three Houses surpass it by having multiple health bars, this final boss has the highest visible HP in the entire series, at a whopping 200.
Duma
With how widespread its relevant bug was to steal some rather strong items, not to mention its limited actual utility, it's no wonder this item never returned after Blazing Blade.
Mine
Due to space limitations, this unintentionally funny sentence displays after Seliph receives wisdom from the ghosts of his parents.
Seliph got a Life.
This unique sword of Ike's has no special ability, but it is notable for confusion regarding its localized name.
Ettard
Mario Kart Double Dash Bonus Disk
This Echoes combat art provides the highest fixed number printed across any Fire Emblem game, in reference to an odd quirk in Gaiden.
Lunar Flash
Fire Emblem Echoes has an invisible "Deicide" skill given to the Falchion, which lets it pierce Duma's invulnerability. However, as a nod to a glitch in the original, it also exists on this spell.
Nosferatu
Many players found themselves baffled when, after following Leif's advice, finishing this type of map left the poor kid alone.
Escape
One of many Star-ranked weapons in Thracia, this axe single-handedly rockets Osian to viability, which is a miracle considering the fan translation completely butchered its name.
Vouge
This 2015 3DS game allows you to get Fire Emblem units by scanning in Amiibo. It also has... Abraham Lincoln?!
Codename S.T.E.A.M.
The lowest non-zero Growth Rate in the series, shared by multiple Shadow Dragon units as well as Binding Blade's Barthe.
2% Resistance
Though speedrunners would likely play the Japanese version anyways for text scrolling reasons, this Path of Radiance bug makes it drastically faster than overseas versions anyways.
Negative Critical bug.
The New Mystery of the Emblem fan translation caused quite a stir when they debated changing this barely-relevant unit from BS Fire Emblem's name to Vergil.
Belf
Veyle's second personal weapon, the only one truly exclusive to her, and the only magic dagger in the game.
Misericorde
Fire Emblem Fates added the Lords from some prior games via scanning in amiibo, but it also added this legacy character via the Cipher trading card game.
Minerva
Despite nearly nine years of powercreep, this unit from the first months of Fire Emblem Heroes still maintains the highest HP stat in the game, with enough love from a player even allowing him to hit the in-engine cap.
Arden
If the player has unreasonably good luck, it's possible to save Eyvel from her fate early in Thracia. However, it requires this extremely unlikely circumstance to occur.
Nanna gaining 5 levels of Constitution.
The original Binding Blade translation for what the current translation calls "Unhuman," the initial term for Manaketes.
Human not Human.