Impa's armor was stylized with a Japanese motif. Early concept art shows that Impa's was conceptualized as a samurai, having the Naginata as the main weapon, as well as design elements from her Skyward Sword incarnation.

Many of Impa's moves and combos are likely inspired by the bodyguard/protector characters from Dynasty Warriors, Samurai Warriors, and Warriors Orochi. Her victory sequence with the Blade may also have been inspired by a move done by a character in Dynasty Warriors 8.
Contributed by DrakeVagabond
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In the 3DS port pressing the L, R, X, Y, and B buttons instead of the A Button on loading screens in the game's Adventure Mode, produce a different set of musical notes, which all match up with the Ocarina from Ocarina of Time and Majora's Mask. Like those games, the notes can be stringed together to make music, which includes all of the Ocarina Songs that were featured in both those games, making it possible to recreate classic Ocarina Tunes.

It's also worth noting that the button inputs match up with the 3DS Remakes of both of those games, but with the B Button taking place of the A Button.
Contributed by CuriousUserX90
The character Linkle was originally created during the development of Hyrule Warriors. She was originally conceived to be Link's younger sister, but the idea was scrapped due to Eiji Aonuma not wanting her inclusion to conflict with Wind Waker Link's sister Aryll. After the game's release, sketches of her concept were included in the boxed editions' visual databook and she escalated into popularity within a portion of the Zelda fandom. Despite being incomplete at the time, she was one of the popularly requested characters during the open call for playable candidates posted onto the game's Twitter. When re-pitched to Aonuma with a revised backstory, he approved her.

Former Nintendo localizer Chris Pranger stated on his Twitter that Linkle was the last character he wrote before leaving Nintendo. He expressed excitement for her debut, adding that he liked writing for her more than he did Lana.
Contributed by DrakeVagabond
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In promotional art for the Legends expansion, there was a crossbow hidden behind Link's scarf. This was a hint that Linkle was being planned to be playable before her reveal during a Nintendo Direct event.
Contributed by DrakeVagabond
Links design and moves in the game are heavily influenced by the character Zhao Yun from the Dynasty Warriors series. Both are clad in green, wear long scarfs, and are the main heroes of their respective franchises. Many of Link's iconic moves are based on Yun's combos.
Contributed by DrakeVagabond
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Impa's armor was stylized with a Japanese motif. Early concept art shows that Impa was conceptualized as a samurai, using the Naginata as a main weapon, and used design elements from her Skyward Sword incarnation.
Contributed by DrakeVagabond
One of Link's unlockable weapons is the 8-bit sword and shield, which are based off of the sprites for the wooden sword and shield from The Legend of Zelda on the NES. However, the shield has been edited, the christian cross on the original sprite for the shield has been replaced with four squares in the center, possibly to avoid religious controversy.
Contributed by MarioManiac88
Darunia's victory sequence is a reference to The Legend of Zelda: Ocarina of Time, where Darunia dances happily when Link play Saria's Song.
Contributed by DrakeVagabond
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On page 246 in the Hyrule Warriors Japanese Art Book there is concept art depicting Link's shield having some sort of spirit who would work as Link's partner.

Another piece of concept art shows that they might have absorbed the blood of enemies Link cuts down, although the precise details are unknown.
Contributed by Spinjitsuninja
Eiji Aonuma stated on Miiverse that he felt sad that Midna's beautifully designed true form character would make such a minor appearance in Twilight Princess. He claimed he was happy to see Koei include her in Hyrule Warriors, as he had always wanted to have an excuse to have her appear in another Zelda game, but could never figure out how to do so due to the ending of Twilight Princess.
Contributed by DrakeVagabond
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An early screenshot shows the Lizalfos enemies with the designs from Skyward Sword as well as a differently designed Heads Up Display.
Contributed by DrakeVagabond
Youske Hayashi had stated in an interview with Game Informer that both Zant and Girahim originally were not going to be playable. However, ##Tecmo Koei## ended up adding them to the roster in response to fan feedback.
Contributed by DrakeVagabond
Using the weapon switching glitch with Zelda using Lana's Summon Gate will cause her to hum her theme song while preforming a combo.
Contributed by DrakeVagabond
During Nintendo's E3 2014 Nintendo Treehouse event, Midna was shown having two separate weapon slots, hinting at her having an additional moveset, while in the final product she only has one. It is currently unknown why her second slot was removed.
Contributed by DrakeVagabond
There is a glitch in the game that allows players to swap weapon types with others characters.
Contributed by DrakeVagabond
There is a glitch when preforming Zant's combos. When his Special Power Meter is full and he performs a special attack right before an enemy's intro cutscene, the special meter will freeze and Zant will infinitely spin.
Contributed by DrakeVagabond
When Omega Force began making the game, it contained many core Zelda elements such as puzzle solving and an RPG approach. Shigeru Miyamoto intervened at this point, saying "this doesn't feel like a cross-IP game, this is more just like a Zelda game" and that if it was just going to feel like a Zelda game, there was no point in doing a cross-collaboration.
Contributed by DidYouKnowGaming
The game's producer, Yosuke Hayashi, stated that he is a huge fan of the Zelda series, and viewed the Hyrule Warrior's development process as making 'the official Zelda fan game.'
Contributed by DidYouKnowGaming
##Tecmo Koei## previously developed multiple games in which they incorporate other IPs into the realm of Dynasty Warriors, such as One Piece: Pirate Warriors. Coincidentally, Tecmo Koei approached ##Nintendo## about creating a Zelda version of Dynasty Warriors just as Zelda series producer Eiji Aonuma was playing one of the previous Dynasty Warriors IP crossover titles. Aonuma was himself considering the potential of a Zelda game with Dynasty Warriors style gameplay at this time.
Contributed by DidYouKnowGaming
The game does not take place within the traditional Zelda timeline. Rather, it exists in a separate dimension with a link to the known Zelda timeline. Characters are pulled from the standard timeline into this new dimension as a part of the story. Zelda series producer Eiji Aonuma likened it to how characters in The Avengers all have their own stories, but are pulled together to form a new story.

Within the Zelda canon, there is the timeline, but there has always been the sense of the main story and kind of a side story. Like, Majora's Mask might be considered part of that, though it does exist as part of the timeline. With Hyrule Warriors, there is a link between the two, but it exists as a separate dimension, so it doesn't exist as part of the main canon. Lately I have been thinking of it similar to The Avengers. - Eiji Aonuma
Contributed by DidYouKnowGaming
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Concept art of a female version of Link appears in the Hyrule Warriors artbook. Named as "Linkle", or "Rinkuru" in Japanese, she is described as being "little sister-like". Her design includes a crossbow (also demonstrating that she would have been right handed, whereas Link is normally left handed), and a coat in place of Link's signature tunic.

Linkle was later announced as a character for Hyrule Warriors Legends, the Hyrule Warriors 3DS rerelease.
Contributed by Dazz
There were originally plans for a stage in which the player simply chops grass. However, the stage never made the final cut.
Contributed by CuriousUserX90