WARNING: The following contains spoilers for Episode 18 of Digimon Adventure 2020, "Countdown to Tokyo's Annihilation," now streaming on Crunchyroll.
Over the course of two episodes now, the DigiDestined have been locked in an intense struggle against a particularly slippery enemy. After luring Tai, Izzy and Mimi into an artificial version of Tokyo in the Digital World, Eyesmon, a villainous Champion level Digimon, proved to almost be too much for their Ultimate-level partners to handle -- even when the rest of the gang showed up to support the trio. We also discovered that this digitized manifestation of Japan's capital was the cause of the real city's blackout. Digivolving again to Orochimon in the last episode, it appeared to be dealt a killing blow by a suped-up WarGreymon.
However, in Episode 18, "Countdown to Tokyo's Annihilation," we learn that this isn't the case. Instead, Orochimon achieves a level that the DigiDestined's individual Digimon have not achieved in the reboot series so far: Mega. An enemy of this magnitude requires a hero of equal power. Luckily, the series already has such a hero it can call on. Omnimon's back! But he's not the only blast from the past the episode features.
Debuting in the first Digimon movie, Omnimon -- the Mega-level fusion of WarGreymon and MetalGarurumon -- made a surprise appearance in the reboot series' second episode but hasn't been summoned since. The fan-favorite knight's presence always seems to coincide with mysterious clocks that countdown to Tokyo's "annihilation." One such clock did just that at the anime's start as nuclear warheads were directed towards the city. At the end of Episode 17, the clock reemerged, counting down from 10 minutes. Drawing even more power from the real world, Orochimon's Mega form, Nidhoggmon, causes chaos with people's smartphones in Episode 18 -- possibly creating a cyberterrorist attack of a more intimate, but nonetheless devastating nature this time.
Though Nidhoggmon is a kaiju-sized monster that dwarfs Omnimon, the caped warrior handles it with consummate ease. In fact -- true to his knightly nature -- he ends up cleaving the beast in twain. With the final (we hope...) strike dealt, fake Tokyo is finally destroyed. But the DigiDestined have little time to celebrate. After Omnimon's victory, another clock starts up -- this time counting down from just one minute. A portal opens up in the sky, sucking all of the DigiDestined through it. Only Tai and Matt are spared, shielded by Omnimon's all-purpose cloak.
It's here that Devimon, the original series' first Big Bad, makes his first physical appearance in front of the characters. Forming his body out of the desert sand (ala The Mummy's Imhotep) where the city once stood, he delivers a stark warning to the shocked boys, trying to dissuade them from their quest to find the Holy Digimon. Elsewhere, we get a glimpse of a tall, creepy tower, which could well be the reboot's redesign of Devimon's mansion from the original series, as well as where he's transported the other members of the group to. As Digimon Adventure edges toward its final batch of episodes, Devimon will undoubtedly begin to feature far more.