There is an impressive amount of evidence, both from interviews and the game's data, of many elements, features and similar content which experienced changes during development:
- Originally the game was going to use a mechanic called "Formations" where the unit would use a squad of NPC like soldiers that would adjust their formation to do various effects that the player could use in battle, such as attacking from a distance, charge over the enemy, or use other effects. The feature was shown in the initial trailer, but during E3 2019, it was revealed that this feature was scrapped and changed to the Battalion/Gambit system instead, which focuses on individual moves and roles instead of formations.
- The reveal trailer shows a few elements that were changed before the game's release.
- Mercedes was intended to have brown hair, and not the blonde hair she has in the final version.
- Ashe was going to be part of the Golden Deer before being switched to the Blue Lions at some point. Given Ashe's backstory and commoner status, this implies that early on Lonato would have been from the Leicester Alliance, before the choice was made to make him from Faerghus.
- Edelgard was originally supposed to start with Magic of some kind, based on her having the ability to use Magic on the menu in the trailer, but instead Edelgard's Magic skills start too low to cast any spells in Chapter 1.
- Crit animations originally were framed as a large amount of the character model looking towards the center of the screen as it zooms in towards the user's face.
- A Nintendo
Dream interview revealed multiple tidbits:- Garreg Mach Monastery having an underground labyrinth of sorts (known as Abyss in-game) was planned very early into development but ended up getting cut in the initial release due to the enormous amount of content already present in the game. Its reintroduction through the DLC waves came because, while developing Cindered Shadows, the developers desired to bring back the ideas they had initially omitted.
- Unlocking the option to access the Crimson Flower route was originally meant to be a lot more complicated. One of the developers stated the method in the final game is "about 3 times as easy to follow" as their original concept, since the game would never telegraph at any point that an exploration event could trigger a route split.
- Claude's role in the story was meant to be much different than it was in the final product, hinting that Claude was meant to be more villainous, but still carried the same goals of unification and finding somewhere to belong for himself that he had in the final product. This is why a lot of media/descriptions about him played up his trickster traits so heavily, whereas in the final product, he's mostly just a light troll at times.
- In a related note, the Golden Deer House was initially conceived to be far more dysfunctional than it ended up being, as they were planned to act as a microcosm for the Leicester Alliance.
- There was originally meant to be a scene where Nader reveals that Claude's real name is Khalid, but it ended up not fitting anywhere in the story.
- Rhea was meant to be shown as being really fond of animals and originally had a bathroom full of animal items. This ended up scrapped, but might have influenced the large number of cats and dogs that appear in Garreg Mach.
- The reason why Edelgard is the only other character in the game other than Byleth with the Crest of Flames is because originally she was supposed to be able to interfere with Byleth's Divine Pulse ability.
- Dimitri wasn't initially going to have an eyepatch after the timeskip, and the decision to give him one was taken later in development. Similarly, it was decided that he wouldn't get one during Edelgard's route as a means to communicate that he went through different experiences compared to non-Crimson Flower routes.
- Fire Emblem: Three Houses - Fódlan Art Book reveals Almyra has a unique banner of its own◊ which was never used in the game proper. On a similar note, the banner of Miklan's thieves exists in the game's data◊ among the other banners, but ended up never used during gameplay (keen players can still catch a glimpse of it during one of the game's cutscenes however).
- Datamining the game has also revealed multiple aspects, scenarios and features that never made it into the final game:
- The fact Jeralt, Rhea, Seiros, and Sothis have multiple unused lines as playable characters heavily suggests they would have been playable in some manner early into development. Sothis especially stands out since she is not playable in any form and only appears in battle when Byleth uses the Sothis Shield ability.
- Characters were originally going to able to die pre-timeskip, as evidenced by every character having been coded to call different death quotes specific to their Academy and War Phase.
- Both Byleths were supposed to access the Dancer class at one point, but in the final game, the Dancer class is only available to students. This appears to be because Byleth has a high Charm stat and growth, meaning Byleth would win easily by the time of the event, and so to make things more fair, was prevented from entering, alongside being a professor and not a student like the requirement states. The 4th DLC wave gives them the option to dress as a dancer, though not take the class.
- There are hints Hilda was briefly considered to be recruitable during the Crimson Flower route. For starters and, unlike Seteth, Flayn, Catherine and Cyril, who are also unavailable during said route, she has a written epilogue between her and Byleth exclusive for the route. Also, her A-Support with Byleth is coded to be unlocked as soon as Chapter 14 in CF rather than Chapter 16 like in other routes, likely to account for the path's short length.
- There's some data hinting that, besides Edelgard and Hubert, the rest of the Black Eagles would've also become enemies in the Silver Snow route under specific circumstances. For one, in the route's version of Chapter 13, if any of the Black Eagle students fell in Part I while playing in Classic Mode, Edelgard will make mention some of her former classmates defected to her side after the timeskip, which never comes to pass in actual gameplay as the game considers the units dead rather than unrecruited. Second, the path's version of the event "The Death Knight" has triggers to make Caspar and Linhardt appear in the cutscene alongside the titular Death Knight if the game considers them unrecruited, which is a quirk both characters also have in the Azure Moon and Verdant Wind versions of this event. And third, both Silver Snow and Verdant Wind have near identical enemy data for their shared maps, meaning it's possible via hacking to restore this feature to an extent.
- Silver Snow's Endgame was at some point more difficult than it ended up being in the final release. Unused text indicates that, along with the southern stronghold, the east and west ones were also able to spawn monster reinforcements at one point, with each tile needing to be blocked off separately to stop them.
- Apparently there was going to be a scenario in which Annette and Felix might defect during the Azure Moon campaign and side with Cornelia's army, forcing you to kill them. Annette because of something to do with her mother and uncle, and Felix being disgusted with Dimitri for the death of Rodrigue, Felix's father, and that Dimitri was technically responsible for it. A similar situation was planned for Lorenz in the Verdant Wind route, as he has unique dialogue against Claude in the Bridge of Myrdinn about being unable to not fight him there as it would be somehow coward from his part, and the route's monastery dialogue for the next chapter has lines for Raphael, Hilda and Marianne referencing the fight. See here how both scenes would've played out in the English version.
- Both Lorenz and Ferdinand have lines for when they share a meal together after reaching an A-Support, even though in the final game their support chain goes up to B, suggesting there was a point in development where they could've potentially reached a paired ending together.
- Circumstantial evidence suggests there were plans to give the Silver Snow route its own version of the Three Houses' rematch in Gronder Field at one point. To start, one of the two unused maps in the game is set to load this location and is internally called as a Chapter 17 of some undefined route. Second, the chapter's spawn data not only has set deployment locations for playable and enemy units only in the Black Eagle slot, the data in question is also present on the spot where Azure Moon and Verdant Wind's Gronder Field 2 battle data is stored, and in the exact same slot. Third, there's a small increase in difficulty between Chapter 16 and 17 on this route which doesn't exist in Azure Moon/Verdant Wind due to the presence of the Gronder 2 mission smoothing the level scaling. Lastly, in the monastery exploration script, there is one empty slot between the Silver Snow and Azure Moon routes, which would've allowed the addition of one more chapter into the route without having to repoint the data used for Azure Moon and Verdant Wind, which are the next paths on the line.
- The Dummied Out Crest of the Forge and Agarthan Crest were meant to enhance the effects of specific weapons through unknown means. Just as its name suggest, the Crest of the Forge is tagged to have compatibility with every forged weapon in the game; meanwhile, the Agarthan Crest is set to enhance the Scythe of Sariel, Athame and Ridill.
- Datamining the Cindered Shadows DLC reveals that all of the game's playable cast have builds setup as if they were usable in the DLC, including weapons and skills. This implies the original idea was that you could take any unit you wanted with you, but likely because of the cost of having to record that much dialogue and work it into the game's story, the choice was made to stick to Linhardt, Ashe, and Hilda instead.
- Multiple leftover text reveals the monastery had a few features that were cut:
- There was originally going to be an additional feature called the Focus System. Each month, the player would chose one of the game's many skills to focus on, and at the end of the month, all of your students would gain experience in this skill. Why it was not implemented is unknown, but it may have interfered with the teaching and goals.
- A horse raising feature was initially planned to be in the game. Not much leftover text exists of it, though the description of a few unused food items suggests the player would've been able at least to feed the horses with those.
- In a related vein, a Horse Riding minigame was briefly considered, though sadly not much information remains of it besides brief mentions.
- It was possible to certificate students for new classes during monastery exploration at one point. It would have required Byleth talking to a scrapped NPC called "Certification Proctor", who was meant to stand outside the Officer's Academy's classrooms.
- There were supposed to be seven group tasks in total. Three of the four were given details while the last one was not; "Fishing Pond", "Greenhouse Upkeep", "Food Procurement". No details exist for what these would have buffed save vaguely implying things like Food Procurement would have increased bow skill due to the flavor text describing it as hunting. Unused item descriptions also hint there were more types of meat meant for cooking the last group task would've provided that were ultimately dummied out.
- There was going to be plans for a birthday party mechanic. It's unclear if it was for the player only or for other students.
- Listening to the game's soundtrack was at one point possible during monastery exploration (specifically, in Manuela's room). The player would've needed to clear a quest in which 4 music sheets named after the four seasons had to be collected and delivered to her.
- A game mechanic that made it into the final product is certain characters having 'special bonds' that grant them extra might in addition to the regular support bonuses, including Ferdinand and Lorenz and Sylvain/Felix/Ingrid. However, data shows that there were plans for special bonds between Hilda and Dorothea, and between Marianne and Bernadetta. This suggests that at some point, there were meant to be support conversations between these duos, but were scrapped for unknown reasons (the fact that Marianne and Bernadetta definitely had potential regarding their self-worth issues while Hilda and Dorothea could logically have a bond over being flirty and gossipy only further enhances the mystery).
- Warriors: Three Hopes' development interviews revealed more scrapped concepts meant for this game which were later revisited in the spinoff:
- Many (if not all) of the story, character background, and lore additions to Fódlan present in Three Hopes were originally conceived for Three Houses, but were never implemented.
- At one point in Verdant Wind, there were plans to have Claude face a "huge obstacle" to his dreams, which never materialized in the game.
