WARNING: The following contains SPOILERS for Invincible season 1, episode 8, "Where I Really Come From."
The Invincible season 1 finale ended with a tease that set up several storylines from the Robert Kirkman comics to appear in season 2. Invincible was renewed for season 2 and season 3 ahead of the April 30th finale, so fans can expect the story of Mark Grayson to continue for at least two more installments. Thus far, the Amazon Prime series has stuck close to the source material, meaning fans of the original comics have an idea of what's coming next in the story.
Invincible is the story of a young superhero, Mark Grayson, aka Invincible. In the first episode, Mark's latent superpowers manifest, revealing he inherited Viltrumite abilities from his father — Nolan Grayson, aka Omni-Man, who is an arrogant superhero with God-like powers. Throughout the course of season 1, Mark learns that Viltrumites are almost indestructible, have extremely high endurance, stamina, and strength, enhanced healing factor, and are nigh-immortal, living for centuries.
Like in Kirkman's comics, Omni-Man in Amazon's Invincible is secretly a villain. In the season 1 finale, episode 8, "Where I Really Come From," he admits to Mark that he is on a mission of conquest, not peace, on behalf of the Viltrumite Empire. Eventually, he leaves Earth — unable to deliver the fatal blow to his son — but where he was headed, and what his "failure" on Earth means, remains unclear. Meanwhile, the final scene between Mark and Allen the Alien laid the groundwork for the next major arc in the series, while a quick montage of villains set up the stories Invincible season 2 will feature. The following are those storylines — without spoilers from the comics.
The Sequids on Mars Will Be Back
Mark encountered the Sequids on Mars in Invincible episode 4, "Neil Armstrong, Eat Your Heart Out" — unwittingly releasing their hive-mind fury on the Martians when he lost track of one of the human astronauts. The Sequids are essentially harmless on their own, but as soon as one attaches to a host, the alien parasites form a hive mind — becoming incredibly dangerous in the process. The Martians were able to avoid this risk, thanks to their shapeshifting ability (and Mark himself is immune, thanks to his Viltumite heritage); however, Earth's humans are very much susceptible — as the ending of episode 4 revealed.
The hint in the Invincible finale sets up two stories to continue in season 2. First, it looks like Mars is overrun by the Sequids, who are gaining strength despite only being attached to a sole host (the astronaut). Two, the reveal that a Martian had impersonated an astronaut in Invincible episode 4 in order to hitch a ride to Earth will likely be resolved in season 2, perhaps with Mark recruiting the Martian to help him deal with the Sequids.
The Mauler Twins Are In Prison — For Now
The Mauler twins are back in prison in the Invincible season 2 finale. The twins were shown entering cells separately during the montage in the Invincible season 1 ending, suggesting that the two have been separated — possibly that they even entered prison at different times. This begs the question — did something happen in the meantime? Robot helped the Mauler Twins escape with Cecil's help — Robot's reasoning is now clear, but why Cecil went along with the plan is currently unknown.
Invincible Season 2 Brings Back The Flaxans
The quick-aging Flaxan invaders were one of Mark's first major adversaries in Invincible. Although Mark and the Teen Team struggled against their forces, Omni-Man had little difficulty fighting off the army single-handedly — then brought the fight to their home dimension. The finale scene indicated that the Flaxan's are still planning an invasion of Earth — and they are angry with Omni-Man.
Doc Seismic Will Return To Face Invincible
In Invincible episode 3, Atom Eve takes down the unhinged villain Doc Seismic, who has some of the series' funniest lines. Doc Seismic was last seen falling into the Earth — where he appears to have recruited some rock and/or lava-based minions. No doubt the memorable Invincible character will return seeking vengeance on Eve — now with the support of a small army.
Titan Will Grow His Criminal Empire
Titan is the petty villain who took over a criminal empire, under the pretense of "helping" his neighborhood. Mark received a harsh life lesson thanks to Titan in Invincible episode 5, "That Actually Hurt," which saw Titan team up with Isotope to take over Machine Head's criminal empire. Cecil was able to acquire technology from Machine Head, and Titan achieved a significant boost in his social and financial circumstances — but at the cost of Mark, Black Samson and Monster Girl receiving grievous injuries.
Invincible Will Face Battle Beast (Again)
Introduced in the same episode that centered on Titan was Battle Beast, who promptly left Earth after almost murdering Invincible (and several of the Guardians of the Galaxy). Battle Beast, a reference to the 80s toy line, is a lion-like anthropomorphic alien who seeks a worthy opponent. He is a fan-favorite from the comics (voiced by Worf actor Michael Dorn!) who appears to be on a comparable level to Omni-Man. Mark was easily defeated in their last encounter, but if he were to return — as the Invincible finale teases — the more seasoned young hero might actually give him a run for his money.
D. A. Sinclair Will Return In Invincible Season 2
D.A. Sinclair returned in Invincible episode 7, "We Need To Talk," which revealed he had teamed up with Cecil. Throughout the episode, Cecil treated the corrupt super-scientist (and murderer) with contempt; however, the season 1 finale showed that Sinclair is not in custody. In fact, he's actively creating more of his "reanimen" monstrosities at the ending of the Invincible season 1 finale. This begs several questions that season 2 will need to answer: where did Sinclair get his "materials," what happened to Rick (did he die?), what is Cecil storing the reanimen for, and was Cecil's disgust always an act?
Cecil Stedman Will Be A Villain In Invincible Season 2
In a telling moment in the Invincible season 1 finale, Cecil Stedman watches D.A. Sinclair working on the reanimen — and smiles. This is a stark contrast to the attitude he portrayed toward Sinclair when others were present, even saying in episode 7 that Sinclair was a "monster" and that just talking to the scientist made him "feel dirty." It was unclear at that time whether or not the reanimen Cecil sent to fight Omni-Man were new creations or the previous victims he had promised to try and help; however, the finale scene confirmed that the Global Defence Agency is actively making more of these monstrosities.
Cecil has been underhanded before — he even bragged about his own ability to lie when questioning Omni-Man — but so far, Cecil has come across as a "good guy" in Invincible. The reveal that his disapproval of Sinclair's work was performative is a major red flag. He came across as kind when talking to Debbie — but he also could be manipulating her, perhaps as a strategy to keep Mark as a resource. This all suggests that Cecil will be a villain in Invincible season 2.