Acting for Two: While mostly averted (as most characters have their own distinct voice actor), there are some exceptions.
The original Soulcalibur saw the introduction of the series' incarnation of Yoshimitsu, voiced by Nobuyuki Hiyama — the voice of Siegfried/Nightmare. It wouldn't be until three games later that this trope remained in effect, as Nightmare and Yoshimitsu respectively were not recasted until III and IV (as shown below).
In IV, Nightmare and Astaroth are both voiced by Michael McConnohie in English. (This is also the case in Legends, though Nightmare and that game's version of Astaroth, Astaroth α, never directly interact.)
Also in IV, Heather Hogan voices Amy and a custom voice.
V gives Nightmare a new voice, but his time around he shares his actors (Yasunori Masutani and Charles Klausemeyer) with Raphael in both versions. This is likely because Raphael (or at least his body) is all but said to be Soul Edge's new host.
For a certain value of "talking", in the GameCube version of II, Nobuyuki Hiyama reprises Link's battle cries as he did in The Legend of Zelda: Ocarina of Time (specifically Adult Link). As Hiyama already voices Nightmare (or rather Siegfried under the Nightmare identity) and Yoshimitsu, they end up sounding very similar.
Actor Allusion: In Soulcalibur IV, Darth Vader fights Mitsurugi in his intro and as a Destined Battle. Toshiyuki Morikawa, Mitsurugi's voice actor, is also the Japanese dub voice of Obi-Wan Kenobi.
B-Team Sequel: Soulcalibur V was the first game not created under the lead of founder Hiroaki Yatoriyama. Instead, it was led by Daishi Odashima, resulting in why V was so different from the other games in tone, story, and characters. Odashima would step down at an unspecified point after V, replaced by Masaki Hoshino, who created the spin-off installments Lost Swords and Unbreakable Soul. Then Hoshino himself departed from Project Soul sometime in 2017, leading Soulcalibur VI to be helmed by Motohiro Okubo, one of the producers of Tekken 7.
Animator Tomoe Yamashita said that Sophitia was his favourite character to design.
Daishi Odashima said, to the surprise of many, that Setsuka was his favorite character. This didn't save her from getting the axe in V. Her style was carried on by Alpha Patroklos, but it's still a shock that she herself didn't make it considering this.
VI lead Motohiro Okubo stated that Mitsurugi is his favorite, as he pertains heavily to Japanese culture.
Creator's Pest: Namco threw PatroklosAlexander under the bus during their 2015 popularity poll, saying that they were "impressed" that the hero of SCV placed so low, even below characters like Dampierre. For the record, he placed #37 out of 45 characters with only 32 votes received out of over 10000 that were cast. Sure enough, Soulcalibur VI turned out to be a reboot that returns to the original setting of the series, and Patroklos was among the first characters (alongside the other V newcomers) that were confirmed to be cut from the game. The original timeline—but the events of V in particular—was then treated as a Bad Future and both Zasalamel and Cassandra are entrusted to Set Right What Once Went Wrong. Additionally, Cassandra is given the honor of naming Sophitia's firstborn, and decides that if the child is a boy, he should be named Deucalion (though this would actually affect Pyrrha—the less controversial sibling of the two—unless the impending timeline changes somehow affect the birth order of Sophitia's kids).
Dummied Out: Daishi Odashima, the game's director, reported that SCV's Story Mode was supposed to be 4 times bigger than that of the released product, and each character would've had their own chronicle instead of just focusing on Patroklos and Pyrrha; time constraints and lack of staff made the plan go down under. They even had fully voiced lines ready for the extensive Story Mode that, in the end, weren't used.
Executive Meddling: The reason we didn't get to see Project Soul's vision for V come to fruition. A few years in, Namco cut PS's funding and staff and then forced Project Soul to release SCV early in order to capitalize on the relatively weak end-of-January market. What Could Have Been, indeed...
Exiled from Continuity: The main reason Necrid never appeared after II. The rights to the character are shared between Namco and Todd Mc Farlane, creating copyright issues that prevent him from returning in future games.
Franchise Killer: Soulcalibur V only barely subverted this. After the backlash and middling sales for its many changes, Namco initially didn't think the series was worth keeping around until convinced by Motohiro Okubo to greenlight another game. That game, Soulcalibur VI, is a Continuity Reboot that undoes everything V tried to do. The reception and sales were positive enough that it saved the same series V nearly killed off.
God Never Said That: A persistent fan rumor, which even circulated through video game blogs like Joystiq, states that Dante was supposed to be a Guest Fighter in III though there is no evidence suggesting the devil hunter's inclusion was ever in the works. SCIII producer Hiroaki Yotoriyama, stated in a March 2005 interview that the game would have no guests (a claim reiterated on the now defunct Soul Archive site), and later specifically singled out Dante as not making the cut (along with Necrid) in another interview featured in Electronic Gaming Monthly #195 from September of that same year. When asked about the origins of this rumor, EGM reports Yotoriyama to have answered "the internet" while laughing.
Keep Circulating the Tapes: Due to the Star Wars license expiring, all DLC for Soulcalibur IV was removed from digital stores. SCIV is one of the few Namco fighting games that is not backwards-compatible for the Xbox One for this same reason.
Soulcalibur was this for the Sega Dreamcast, being a launch title and a Polished Port of the original arcade version that is widely considered to be one of the best-looking, if not the best-looking game of its time, and is one of the highest-rated games on Metacritic. Anyone who didn't buy a Dreamcast for Sonic Adventure was likely buying it for this.
Though Namco fighting games had been PlayStation exclusives at that point (including Soul Blade, the home port of the series' first game Soul Edge), Soulcalibur was only released as a Dreamcast exclusive because it was, at the time, the only console powerful enough to run it. By the time the PS2 came out, the development team was already working on Soulcalibur II, so they decided to skip porting the first game. It did eventually receive an Xbox Live Arcade release, but is still unavailable to PlayStation users.
Soulcalibur II HD Online was brought to the PlayStation 3 and Xbox 360, bringing with them both Heihachi and Spawn for both platforms. The lack of the game on anyNintendo platform (either the Wii U or the Switch) means that Link, the only remaining Guest Fighter, is forever tied to his original GameCube appearance.
Even the Japanese dub isn't safe from this, although it definitely has much more consistency. The biggest change would be the transition from III to either Legends (which only features a handful of returning characters) or IV for reasons yet unexplained:
While Mitsurugi's VA has consistently been Toshiyuki Morikawa, he was briefly replaced by Wataru Takagi in the console version of Soul Edge for some reason.
Hwang was voiced by Toshiyuki Morikawa and Wataru Takagi in the arcade and console versions of Soul Edge, respectively. Takagi would continue to voice Hwang in the original Soulcalibur (possibly due to Divergent Character Evolution between Hwang and Mitsurugi, who was already voiced by Morikawa), only for the role to be recast to Naoki Imamura when Hwang reappeared in III and its Arcade Edition revision. Subaru Kimura would then assume the role for VI.
Real Life Writes the Plot: Very subtly. The Time Skips between Soul Edge and Soulcalibur (3 years) and then between Calibur and SCII (4 years) mirror the real-life gap between each game's release.
Running the Asylum: One could argue that a major factor in the series' steady decline in The New '10s was the departure of its founder Hiroaki Yatoriyama and Project Soul's subsequent reshaping in the wake of his absence.
Soulcalibur V, being the first game whose creation was not led by Yatoriyama, definitely had this feel. His successor, Daishi Odashima, was noted to be a tournament player back during the days of the original Soulcalibur and an avid fan of Street Fighter III: 3rd Strike. His envisioning of the revival of Soulcalibur involved the decision to carry out a 17-year Time Skip (one admitted to be arbitrary by Odashima himself), which replaced many longstanding and popular veterans with younger, more anime-inspiredsuccessors (many of whom were criticized for being one-note), and the story revolved around Patroklos, son of Sophitia, in his quest to save his sister Pyrrha. Many pointed out that it felt more like personal fanfiction becoming reality, as opposed to being a true sequel to Soulcalibur. (He did want to call it Soul Edge 2, after all.) SCV also relied heavily onStreet Fighter-influenced mechanics, most notably the inclusion of meter and Supers and alterations to the Guard Impact mechanics, changes that proved controversial. Odashima would leave Project Soul after the game's lukewarm reception, with Masaki Hoshino taking his place as the new series director.
Meanwhile, the Hoshino-led Project Soul tried its hand at rectifying some of the controversyby bringing back several of the omitted warriors, but their marketing was centered around sex appeal, and in volumes far beyond previous installments; even Soulcalibur V wasn't as blatant, and two of its posters featured nothing but Ivy's barely covered ass and fur-wrapped breasts. Neither Lost Swords nor Unbreakable Soul were received favorably by the fanbase, and Hoshino would also leave the team in 2017, making it hard to gauge his impact on the franchise as a whole.
The gap between V (late January/early February 2012) and VI (mid-October 2018) is the longest in series history, spanning almost seven years.
In another sense, as VI is more of a sequel to the original Soulcalibur games (and Soul Edge) than the Soft Reboot that was V, one could say it's been ten years since the last "main" installment Soulcalibur IV (released at the tail end of July in 2008).
Serendipity Writes the Plot: Due to the litigation trolling from Tim Langdell and Edge Games over use of the word "edge" as it pertains to video games, Namco opted to name the sequel to Soul Edge/Blade to "Soulcalibur" and invented a new sentient sword (the Soul Calibur) to give meaning to the title. That sword has become a prominent player in the series as a result, being the antithesis to Soul Edge's status as the Big Bad (albeit for reasons not necessarily in the interests of the world either). An attempt was made to revert back to the "Soul Edge" name prior to Soulcalibur V but it was shot down due to the brand being too established under its current title.
Stillborn Franchise: Soulcalibur V was meant to be the start of a new direction for the series, and then-head Daishi Odashima planned for follow-ups that would've adhered to that game's status quo. In fact, V was originally going to be called Soul Edge 2 in order to signify this change in direction. However, due to a combination of backlash over the game's story, setting and characters; the series going on a hiatus for many years afterwards; Odashima himself leaving the team less than two years after V; and a general sentiment that the series needed to return to its roots to survive, this did not come to be. Soulcalibur VI would eventually be made, but the game hit the reset button specifically to escape the direction V was going to take the series in and return to the setting that V was trying to shed, which Okubo outright admitted was because the series was on thin ice after V.
A bonus character named Azola was planned for the first game — as a Palette Swap of Sophitia. During development, she was scrapped and her design just became Sophitia's 2P costume. This explains why the first game is the only time Sophitia's 2P costume is a brunette. Azola eventually appeared in IV, as a Create-a-Soul character that features in Sophitia's story and uses her weapon style.
Hwang originally just appeared as a palette swap of Mitsurugi in the Korean Arcade version, and likewise Cervantes wasn't playable. Both were bumped up to playable characters (Hwang getting a move set of his own as well) in a re-release two months later.
Li Long was originally planned to initially return in Soulcalibur alongside with his fellow cast members of the first game and that his storyline would've followed the official canon of the Soul series itself, in that Li Long had survived his battle with Cervantes and spent the next three years recovering before resuming his personal mission, culminating with his emotional reunion with Chie and their son Riki. However, the developers had decided to focus in creating a new character for the game, who would be named Maxi and that Li Long himself would end up being the only original and starting playable character of Soul Edge not to return for Soulcalibur, only making a cameo appearance in "The Tale Begins: Prologue" Art Gallery and being mentioned in Maxi's backstory under the alias Zhang Wu.
When Soul Edge/Soul Blade was renamed to Soulcalibur for the subsequent second game, the original plan was that every game would have a Theme Naming based on swords as opposed to Numbered Sequels. They would instead be marked by the word "Soul" in each title. However, Soulcalibur became such a runaway success beyond their original expectations that they ultimately kept the Soulcalibur name for every subsequent game because of how recognizable it is.
From the early era, there were a ton of designs that didn't see the light of day. However, some feature concepts that may have evolved into future characters, such as a grim reaper-like figure (who may have evolved into Zasalamel), a scantily-clad woman with a whip (who would become Ivy), a feathered man with a rapier (Raphael) and perhaps the record, a girl using a dual-sided weapon that would evolve into the male Grøh two decades later. There's also some odd designs in general, like a kid controlling a large puppet, a female version of Voldo, a woman with what looks to be a chainsaw of all things, and a girl who'd weaponize playing cards. Also, a Yoshimitsu prototype had him appearing as a literal skeleton.
According to II's localization producer, Nao Higo, Cloud Strife was originally supposed to be the guest character for the PlayStation 2 version of the game. However, the deal with Square Enix fell through at the last minute, resulting in Cloud being replaced with the internally-owned Heihachi.
Project Soul originally wanted a Dead or Alive character, likely Kasumi, to be exclusive to the Xbox version of Soulcalibur II as the DOA series was exclusive to the brand at the time, but couldn't get the rights due to then-Team Ninja head honcho Tomonobu Itagaki's feud with Namco over the Tekken series. As a result, they got Spawn to be the Xbox guest character, since they were already partnered with Todd McFarlane to create Soulcalibur II action figures and One-Shot Character Necrid. After Itagaki left Team Ninja, Dead or Alive and Soulcalibur joining forces through guest characters would eventually materialize in Warriors Orochi 3 Ultimate.
A new character named Edgardo was going to be introduced in III alongside Zasalamel, Setsuka, and Tira, but was cut before they could develop his fighting style due to time constraints. Notably, Algol bares a striking resemblance to him. Whether elements of his character were added to Algol is unknown.
There is asubstantial amount of dialogue that was Dummied Out from IV, with many of the quotes being the characters' reactions to various items sold within the shop. This suggests that the mode was originally more complex and interactive, akin to how III had the shopkeeper trio.
Soulcalibur V was originally going to be called Soul Edge 2 in order to mark Daishi Odashima's new direction for the franchise. However, Namco wasn't having it, and forced him to continue the Soulcalibur name.
Going further with the above, the intention was that V would've been a new starting point for the series in general and pseudo-reboot to move the series forward. It was even said that plans were already in the works for VI, VII, VIII and IX. While Soulcalibur VI was made eventually, the game is a Continuity Reboot that undoes everything V tried to do. One can only wonder how different future games would've been if V remained the status quo.
Due to Executive Meddling, as mentioned above, Soulcalibur V was only ¼ finished when it was released. The resulting Obvious Beta was met with a great deal of backlash.
Zasalamel's SCIV model was found on-disc when V was hacked, hinting that he may have been in the game before being removed due to time constraints.
Daishi Odashima originally wanted Bangoo to return as the successor to Rock. However, due to V's rushed development, this never came to be.
V, whilst praised for its great gameplay and visuals, was met with criticism (justifiably so) for the fact that the Story Mode only concentrated on and showcased the fate of a handful of characters. Even its Arcade Mode had no endings for any of the characters, leaving a good deal of storyline elements hanging. Annoyingly, when this was brought up in an interview with game director Daishi Odashima, he stated: "Our first plan on the storyboard was that we had every character's story, and actually we do have it in the studio, but time-wise, man power-wise we weren't able to do it and only one fourth of what we planned to do is in the game"...
Talim was voiced by Kate Higgins in III and IV, who then voiced Natsu in V. Then she voiced Tira in VI, darrining Katie McNulty while getting her original role as Talim darrin'd by Kira Buckland in the process.
Despite being two different people sharing the same identity, Yoshimitsu II shares both his Japanese and English voice actors (Norio Wakamoto and Mitch Urban note Wakamoto took over from Nobuyuki Hiyama, who voiced Yoshimitsu from his Soulcalibur debut, in IV, while Urban was part of the voice actor changing of the guard that occurred during the dubbing of Soulcalibur III) with his predecessor, making them somewhat difficult to distinguish apart from Yoshi II introducing himself as "Yoshimitsu the Second" (and reinforcing the implication that Becoming the Mask is in effect for each successive Manji Clan leader).
that SCV's Story Mode was supposed to be 4 times bigger than that of the released product, and each character would've had their own chronicle instead of just focusing on Patroklos and Pyrrha; time constraints and lack of staff made the plan go down under. They even had fully voiced lines ready for the extensive Story Mode that, in the end, weren't used.