Rick and Morty went deep into its own lore to kick off season six. With so many plot points based on events that happened as far back as season one, you might not remember everything that occurred previously. Whether you’re a Rick and Morty historian or not, the Adult Swim series made one thing clear: its newest big bad has an even more complicated past than we realized.

Rick Sends Everyone Back to Their Original Reality

Season six picked up shortly after the shocking events of season five’s finale. With the Citadel gone and Evil Morty free of the Central Finite Curve, Rick and Morty found themselves stranded in space a la Iron Man and Nebula in Avengers: Endgame. (A movie Rick definitely saw.) Their escape saucer had run out of fuel and food, and their portal gun remained useless thanks to Evil Morty. The two would have died if not for Captain Marvel Space Beth’s timely-yet-corny rescue.

When Rick got home he had to reboot the portal index to make interdimensional travel quick and easy again. That was supposed to be as simple as doing a “a hard reset” on portal fluid. But rather than resetting portal travel, he reset portal travelers. Any person (even the dead) outside their original dimension began growing green before “one way blind hopping” back to their actual home world.

Rick, Morty, and Jerry then vanished, with Summer left to reset the portal navigation system back at the ruins of the Citadel of Ricks.

“Diane” Haunts Rick at Their Home

Rick returned to the dimension where he lived with his wife Diane and their daughter Beth. That’s also where another Rick killed both women, sending Rick C-137 (the show’s main Rick) on his quest for vengeance. (Not before Rick made a computer program of his dead wife’s voice to haunt him. Oof.)

Rick watches holograms of Killer Rick visiting him long ago in his garage on Rick and Morty
Adult Swim

We’d seen Diane and little Beth’s death as a memory in Rick and Morty‘s season three premiere (the infamous Szechuan sauce episode). But it wasn’t until the season five finale that the show confirmed that event was real and had sent Rick C-137 on a destructive path of vengeance and nihilism. Beth and Diane’s death transformed him into the “Rickest Rick” as Morty calls him.

However, despite a deadly search through countless realities, Rick never got revenge on Killer Rick. What we now know, though, is that he did find Killer Rick’s original dimension. And it’s one of the most important in the infinite universe.

Morty Returns to Cronenberg World

In season one’s sixth episode, Rick’s love potion antidote went horribly wrong. It transformed nearly everyone in the world into a David Cronenberg-like monster. Rick and Morty abandoned that dimension for an exact copy where Rick’s antidote worked. But they left behind Morty’s real mother, father, and sister, the only people on Cronenberg World to remain human.

The series revisited Cronenberg World during its loaded season three premiere, where Morty and his new Summer met his former family. Cronenberg World Jerry, Beth, and Summer had become post-apocalyptic warriors, but ended the episode frozen in ice when the Council of Ricks came looking for Morty and Summer.

Season six’s premiere revealed that by the time Rick inadvertently sent Morty back to his original dimension, only his father was still alive. Summer and Beth died shortly after they got out of the ice. But Morty wasn’t the only human Rick C-137 accidentally sent back to that monstrous land. A far great foe had also returned.

Rick and Morty Finally Resolves an Old Jerry Mystery

Adult Swim

In season two’s second episode, Rick and Morty dropped Jerry off at Jerryboree, a special daycare center that had everything a Jerry could want. That included countless other Jerrys from other dimensions, most of whom looked exactly the same.

When Rick and Morty came back to pick up their Jerry, though, it wasn’t clear they took back the same one. Now we know that old gag was no joke – they didn’t. They mixed up their Jerrys, which no one realized until they swapped places again by returning to their original dimensions. That was an eye-opening experience for they Jerry we’ve known since he left Jerryboree. Him and his Beth never separated, leading to an angry, unhappy family.

Season two Jerry still managed to mess things up for his old family, though. He let Mr. Frundles out, necessitating the Smith family to relocate to an exact replica dimension where everyone says “parmesan” weird.

Killer Rick is Cronenberg World’s Greatest Monster

Adult Swim

While this episode revisited old worlds, its biggest moment was a new revelation. The Rick who killed Diane and Beth comes from the Cronenberg dimension; he’s Morty’s actual home world grandfather. Rick C-137 moved there hoping to catch the elusive Killer Rick if he ever came home.

But Killer Rick is “the real deal.” (RIP Cronenberg World Jerry). He doesn’t care about anyone. He was never coming back for his family, so Morty was never bait. And that means the connection he has with Rick C-137 is real, even if Rick tries to deny it is.

Adult Swim

This also means the show’s newest, and arguably greatest villain, is far more intertwined with everything that has ever happened on Rick and Morty than we thought. He didn’t just ruin Rick C-137’s life, he has a personal connection to Morty.

In a dimension full of strange beasts, the uncaring, shifty Killer Rick is the deadliest monster. And his story is just getting started.

Mikey Walsh is a staff writer at Nerdist. You can follow him on Twitter at  @burgermike. And also anywhere someone is ranking the Targaryen kings.