- I Knew It!:
- The Mysterious Girl is indeed Ada Wong, and she's later confirmed to be the new Hero on March 2021.
- Many assume that the game would get new heroes from unrepresented IPs joining post-launch in the future, which was later confirmed on September 2020 with Amaterasu from Ōkami joining as a hero on the following month.
- At least one redditor was able to predict that Oichi would be the next hero after Amaterasu before it was confirmed after the WC2020 Finals. It's more of an unexpected pick compared to previous post-launch heroes.
- Jossed: When Capcom was hit by Ragnar Locker ransomware attack, it was assumed that the next hero announced at the WC2020 finals would be Phoenix Wright from Ace Attorney as a purple one due to several leaks before it was taken down. The next hero turned out to be Oichi from Sengoku Basara as a black one, whose expansion is actually a sequel to Amaterasu's.
- The Other Darrin: In English, Ashly Burch fills in for Laura Bailey as Chun-Li once again after Marvel vs. Capcom: Infinite. However, Bailey reprises her other role as Oichi, thus avoiding Talking to Himself, in a similar vein with MvC:I, where she did not reprise Chun-Li, but reprised her other role as Black Widow.
- Role Reprise: Every character's voice actors from their series and crossover appearances return to voice their character here, in both English and Japanese.
- Ryu is played by Kyle Hebert in English, who's voiced him since Street Fighter IV, with the same applying to his Japanese voice actor, Hiroki Takahashi.
- Chun-Li is played by Ashly Burch in English, having replaced Laura Bailey in Marvel vs. Capcom: Infinite. Fumiko Orikasa voices her in Japanese since SFIV.
- Akuma is played by Richard Epcar, taking the role over from Dave Mallow since Street Fighter V. Taketora, his traditional Japanese voice actor since SFIV, returns.
- Morrigan is played by Siobhan Flynn in English, with Rie Tanaka voicing her in Japanese. Both have played the role since Marvel vs. Capcom 3.
- Jill is voiced by Patricia Ja Lee in English, who notably hasn't played the character since 2011's Resident Evil: The Mercenaries 3D. Atsuko Yuya returns to play her in Japanese, having voiced the character in all video game and live action movie appearances since 2004's Resident Evil: Apocalypse.
- Wesker is played by D.C. Douglas, having been his voice actor since Resident Evil: The Umbrella Chronicles. Joji Nakata voices him in Japanese, who started voicing the character with MVC3.
- Ada is played by Courtenay Taylor in English and Junko Minagawa in Japanese. Both voiced her since Resident Evil: Operation Raccoon City, although Taylor was replaced by Jolene Andersen for Resident Evil 2 (Remake), with Teppen marking the first time she has reprised the role since then.
- X's English voice has Ted Sroka return to the role, who first played him in MVC:I. In Japanese, Takahiro Sakurai plays him, having voiced him since Mega Man X8.
- Zero's English voice is Johnny Yong Bosch, who played him since MVC3. Ryotaro Okiayu plays him in Japanese, having been his sole Japanese voice actor since Mega Man X4.
- Dante is naturally played by Reuben Langdon, his voice actor since Devil May Cry 3: Dante's Awakening. Toshiyuki Morikawa plays him in Japanese, who began voicing the character with Devil May Cry: The Animated Series.
- Nero sees Johnny Yong Bosch playing him as per the norm since the character's debut in Devil May Cry 4, with Kaito Ishikawa playing him in Japanese since the Special Edition of said game.
- Oichi is played by Laura Bailey, her sole English voice actress since Sengoku Basara: Samurai Heroes. Mamiko Noto plays her in Japanese since the character's debut in Sengoku Basara 2.
- Talking to Himself: In English, Nero and Zero are both voiced by Johnny Yong Bosch.
- The Wiki Rule: The TEPPEN wiki.
- Working Title: Known as "Project Battle" in the early alphas sent to prominent members of the Fighting Game Community.
Trivia / TEPPEN