WARNING: The following contains spoilers for Episode 35 of Digimon Adventure 2020, "The Glowing Angewomon," now streaming on Crunchyroll.
As if the episode's title wasn't enough of a giveaway, Digimon fans that have gotten a handle on the reboot series' pacing by now would have been expecting Angewomon's arrival as soon as Gatomon (Tailmon) was added to Tai's party two episodes back. Angewomon is definitely given her angelic moment to shine in Episode 35 against a deepsea version of the Devimon species; however, the Ultimate Digimon's reintroduction to the Adventure anime is arguably upstaged by a single silhouette later on.
During "The Glowing Angewomon"'s Digimon Encyclopedia section -- a cute but mostly throwaway segment at every episode's end -- Izzy's narration gives a glimpse at which Digital monster he'll breakdown next week, ahead of Episode 36's preview. So far, these silhouetted forms have been easy to recognize, either because they're characters who've recently been brought into the series, or through the audience's familiarity with prior series'. But this form is neither. Instead, it looks like Digimon Adventure 2020 is about to welcome a game-only variant of WarGreymon to animation for the first time.
Close inspection of the silhouette reveals unmistakable similarities to BlitzGreymon, even without its hot rod-red coating: the head alone connects it to the Agumon evolution line, while the guns-for-arms and guns-for-knees (guns for everything!) make the link to BlitzGreymon all the clearer. Though it's been included in a number of Digimon video games -- and more recently, the TCG -- the Mega-level warrior might be most recognizable to players of Digimon Masters Online, which the form was made available for in December 2018. Digimon Linkz, an RPG first released in 2016, describes it as a "subspecies" of WarGreymon, meaning that like Pegasusmon, BlitzGreymon is more of side evolution (in the new canon, at least) than a step up the evolutionary ladder.
This description also notes that the form "can destroy even the sturdiest of structures," which may dovetail nicely into what the preview of Episode 36 hints it may be used for: the ISS problem. Masters players may also point out that BlitzGreymon can supposedly only derive from Black Agumon, which Tai's partner is not. However, this doesn't appear to be a requisite in other games that the Mega form is used in. Plus, Digimon Adventure 2020 has been playing by its own rules from the start. There's no telling what will or will not remain in-canon.
As if this striking scarlet hero isn't exciting enough for anime fans, something else to consider is what its all-but-confirmed debut means for Garurumon and the pair's combined form, Omnimon (also known as Omegamon.) Like WarGreymon, MetalGarurumon has a similar alternate Mega form that works in tandem with BlitzGreymon -- CresGarurumon. Together, the two can fuse to become Omegamon Alter-S, described by the Digimon Reference Book as a "new side of Omegamon," and first introduced to the franchise in 2017. If this alternate fusion is indeed on the cards for the reboot, it would explain why the series brought out Omnimon so early on. The iconic Digimon's original iteration may have just been an appetizer, all along, to whet our appetites for the main course.