Ascended Fanon: The identity of Unknown has been discussed for a long time among fans. Eventually, the most popular rumor that she's a One-Winged Angel version of Jun Kazama was made canon.
Box Office Bomb: The film's budget was $35 million. Its box office take? $1,696,665. Never theatrically released in America, the poor showing was especially incredible in Japan.
Cowboy Bebop at His Computer: Upon the release of Tekken 5, a Spanish magazine launched an article about the characters of the game, which turned out to be a specially atrocious example of misinformation. The article had Craig Marduk labeled as "Marshall Law", presented Ling Xiayou as come from the future (presumably a misunderstanding from her goal to build a time machine to change the past) and said that Yoshimitsu was Ogre's son.
Cross-Dressing Voices: Ironically, while Tekken Tag Tournament 2 clarifies beyond a shadow of a doubt that Leo is a woman, her speaking lines are voiced by a male German-speaking actor in the game. Her battle cries are still those provided by Veronica Taylor back in 6, however (see The Other Darrin below).
Descended Creator: Katsuhiro Harada himself initially voiced the battle cries for Law and Yoshimitsu back in the first three games up to Tag. He stopped doing so starting in 4 since he says he's no longer capable of replicating those sounds.
Mystic Manly Heihachi Muthafuckin' Mishima Bentley, Jr., which is usually abbreviated as Mystic Man Bentley or MMB.
Polish players reffer him as Heniek/Henio, which is a diminutive form of Henry.
Puertoricans (who have a VERY healthy and active Tekken-playing community) call him "El Viejo Cabrón", which roughly translates to "The Fucking Old Guy." The word cabrón in Puertorican Spanish can refer to both someone who's completely awesome and someone who's a complete dick... both apt descriptions for Heihachi.
Due to Hwoarang's name being hard to spell by western players he got nicknamed Bob. But now that there's an actual Bob on the roster... Fans now spell Bob (the nickname, which stands forBoy On Bike) as BOB to differentiate it from the actual character.
When Jaycee was first revealed in the initial trailers for TTT2, she was given the nickname "Queen" in deference to the existing male luchador King.
God Does Not Own This World: Seiichi Ishii, the original director and lead designer of the series, left Namco shortly after finishing Tekken 2 and has not been involved with the series since then.
AshKetchum joined the King of Iron Fist Tournament 6?role Taylor provided the voice of Eleonora "Leo" Kliesen for 6, but was replaced by a German-speaking voice actor for Leo's new lines Tekken Tag Tournament 2 (the battle grunts are still Taylor's).
Dr.Tenma joined the King of Iron Fist Tournament 6?role O'Brien provides the voice of Miguel. Like Veronica Taylor above, he was replaced with a Spanish-speaking voice actor for Tekken Tag 2 for Miguel's new lines, but the battle grunts are still O'Brien.
This counts as a Playing Against Type for Suwabe. Most of his usual roles are villains or someone who's rather fucked up in the head or prone to angst, at least an Anti-Hero. Lars is a straightforward heroic good guy.
Paul shares a voice actor with Kalas in latter games.
I Knew It: Kazumi being the name of Kazuya's mother was all Fanon, until Tekken 7 that is.
Jossed: The Tekken 3 intro, if you read into the Poison Oak Epileptic Trees that this is Jun's severed head, doesn't gel with the fact that she is alive and well according to the Tekken Tag Tournament games. Interviews prior to Tekken 7's release confirmed that she is alive and returning to the series.
Keep Circulating the Tapes: Tekken 3 is the only PS1-era game that isn't available as a P Sone Classic on the Playstation Store. Harada mentioned that, as much as he'd like to have it rereleased, certain difficulties were preventing it from coming out (most likely licensing issues involving Gon).
Name's the Same: Here's something interesting. One of Jun's command techniques in Tag 2, the Housenka (uf+4,3 for those familiar with Tekken move notations), is the same name as one of Chun-Li's ultra combos.
The Other Darrin: For reasons Harada exasperatedly describes at length here in response to irrationally dimwitted fans with unrealistic expectations, it shouldn't come as a surprise that given how many years this series has spanned, the developers couldn't possibly retain the same voice actors for the majority of the characters even if they wanted to. There's also a weird case of this in Tag 2 wherein the returning European-language-speaking characters (Eddy, Christie, Lili, Miguel, Leo) now have lines in their native tongues, yet still retain their original battle cries from 6.
Averted in Kazuya's case. Contrary to what The Other Wiki and other sources tell you, Toshiyuki Morikawa has not been voicing Kaz since 4. It is Masanori Shinohara and it always has been Shinohara. According to the Japanese Wikipedia, Joji Nakata voiced Kazuya back in 1-2 and Tag.
Marshall Law's voice actor (not counting the high-pitched warcries) changed from Robert Clotworthy in 5 to David Vincent in 6. And recently Harada stated in an interview that for the longest time he did the battle cries for Law.
Shiho Kikuchi voiced both Kunimitsu and Jun in 2 and Tag. As of their reappearances in Tag 2, they're now voiced by Houko Kuwashima and Mamiko Noto respectively.
Back in 4, Anna was voiced by Lenne Hardt, the woman responsible for Axl in Mega Man X7. Fortunately, she is decidedly sexy as Anna. She later got replaced in 6 by Tara Platt, who voiced another Namco hottie—Setsuka.
Christie was originally voiced by Xanthe Smith, who was replaced by Lisle Wilkerson after 4. As of Tag 2, she now has a Portuguese-speaking voice actress.
Xiaoyu was originally voiced by Yumi Touma from her debut in Tekken 3 all the way to Tekken 6. The role was recast to Maaya Sakamoto in Blood Vengeance. It seems like this will stick, as Sakamoto reprised her role in Tekken Tag Tournament 2.
According to the Tekken 6 artbook, Unknown was meant to be Jun's younger sister. This was dropped when TTT became a spin-off. TTT2 then reveals Jun herself is Unknown.
Steve's prototype name was the outlandish "Dean Earwicker", which earned a substantial amount of negative feedback from the Tekken community. It was changed to the more natural-sounding Steve Fox. As a nod to this both a Tekken Force member in 4's Tekken Force Mode and a Tekken Lord Steve in 5's Arcade Mode go by the name of Dean Earwicker.
Harada had wanted to release Tekken Revolution for the Xbox360, but Microsoft turned down the offer.