In July 1999, the industrial metal band Powerman 5000 wrote and released the single "When Worlds Collide", which would become one of their signature songs.

On February 23, 2016, patch version 3.2 of the "Heavensward" expansion for Final Fantasy XIV Online would be released, entitled "The Gears of Change". During the Containment Bay S1T7 trial, there is a boss fight against Sephirot, the Fiend, in two phases. The first phase's music is a rearranged version of "Battle to the Death", a boss theme originating from Final Fantasy VI where Fiend first appeared, while the second phase's music was an original song entitled "Fiend", composed and arranged by Masayoshi Soken with lyrics by Michael-Christopher Koji Fox.

The same day, a thread was made on Square Enix's forums noting the similarities between "Fiend" and "When Worlds Collide". Powerman 5000 were somehow informed of this and took to Facebook on February 24 to accuse the game's developers of ripping off "When Worlds Collide" while writing "Fiend". They claimed they were only making these allegations because the song was used in a video game, stating "If it was a song made by a fan, we wouldn't care." After the story gained traction and several mixed responses were put against Square Enix and Powerman 5000, the band's frontman Spider One made another Facebook post on February 25 revealing that the band would not be taking legal action against Square Enix, while emphasizing that their original post was "Just an observation" about "a piece of music that was way too similar to be coincidence" and there was "no cry for attention or publicity", before briefly advertising their upcoming tour dates in March and April.

In response to the controversy, the game's producer/director Naoki Yoshida released a statement in the original forum thread that spurred the controversy explaining how they created "Fiend", and stated that Soken claimed to him he was unaware of "When Worlds Collide" when writing the song:

According to Final Fantasy XVI's creative director/scenario writer Kazutoyo Maehiro and the game's producer Naoki Yoshida in a 2023 IGN article, in the Japanese version of the game, Chocobos are referred to as "uma" (馬), which is the Japanese word for "horse". Initially, neither Maehiro or director Hiroshi Takai considered using Chocobos in the game at all, because according to Maehiro, "when thinking about the story, the worldview, and a feeling of reality, a horse just looked better as a silhouette when straddled." Yoshida elaborated that horses fit better when building a world based on European medieval gothic fantasy:


Despite this explanation, Yoshida still instructed the development team to include Chocobos in the game in an effort to stay faithful to the series' long-standing elements. The Japanese version also still refers to them as Chocobos and horses interchangeably. Maehiro stated that he tried to tie the Chocobos into the history of Valisthea through partnerships with its people, in an effort to create something culturally familiar. He justified this by stating that in Japanese, they "sometimes refer to a car as 'legs', or not having a car as 'having no legs'; and in the same way, the people of Valisthea refer to Chocobos as 'horses'." He subsequently implied that actual horses may exist in other regions in the game's world, but that in Valisthea, Chocobos function as their regional equivalent to actual horses. Localization director Michael-Christopher Koji Fox also stated that he decided not to refer to Chocobos as horses in the game's English translation:


The terminology in the decision to refer to Chocobos as horses resulted in confused or joking reactions from Japanese players online, since this is not the first time Chocobos were referred to as horses in the series. In the original 2010 release of Final Fantasy XIV Online, the kanji characters for horse and bird (鳥 , "tori") were used together as "horsebird" (馬鳥) in the Japanese script in place of the standard katakana for Chocobo (チョコボ). At release, several other katakana terms were replaced with kanji symbols, with some terms existing in-game as written in Chinese rather than Japanese. Square Enix offered several conflicting explanations for the changes, including the need to "build atmosphere", and to consolidate terminology with the then-upcoming Chinese-language release, but these did not help as the change caused an uproar among Japanese players, resulting in Chocobo being reincorporated into the Japanese version's script in a future update. The controversy would later be referenced in the 2013 reboot of Final Fantasy XIV Online through a piece of dialogue spoken by Golden Uma Doshin, a Quest NPC found in Central Shroud as part of the limited time quest "Turn Around, Beautiful":

The Sage Job introduced in the Endwalker expansion pack had its icon changed prior to the expansion's release due to player feedback. Originally it featured holes in the nouliths represented on the icon, however due to concern from players who suffer from trypophobia, a phobia towards clusters of small holes or bumps, the game's director Naoki Yoshida felt compelled to have the holes filled to ensure all players felt comfortable in the game.