This story contains spoilers for Episode 7 of Agatha All Along.

“Agatha All Along” has made it clear throughout the series that death comes for all of us. And in the Marvel Cinematic Universe, it turns out, death comes in the form of Aubrey Plaza.

In the seventh episode of the Disney+ series, aptly titled “Death's Hand in Mine,” the rest of Agatha's (Kathryn Hahn) makeshift circle finally learns that the mysteriously dangerous but charismatic Rio (Plaza) has always been Death. When fortune-telling witch Lilia (Patti LuPone) performs a final tarot reading to complete her quest, the psychic realizes the true identity of her wayward traveling companion.

“Rio. She is death,” says Lilia after saving her coven from impending impalement.

When asked to confirm, Agatha admits, “I like the bad boys.”

As seen in Lilia's visions, Rio's identity has been hinted at repeatedly in previous episodes. The most obvious of these clues is the Ouija board, which illustrates the presence of DEATH in Episode 5.

In the final moments of Episode 7, Lilia urges Agatha, Billy (Joe Locke) and Jen (Sasheer Zamata) to continue the path of the witches and all the other trials that await them.

Now that we know that all roads lead to her, here's everything you need to know about Death and his backstory.

Who is Death?

Things tend to get intense between Rio (Aubrey Plaza), left, and Agatha (Kathryn Hahn).

(Chuck Zlotnick / Marvel)

In Marvel Comics, Death (with a capital D) is a cosmic being who embodies death and mortality. The character first appeared in Captain Marvel #26 by Jim Starlin and Mike Friedrich as a disguised cohort of Thanos. Yes, that Thanos.

While other interpretations of Death have appeared in Marvel stories, this cosmic take on the character can be traced back to the 1973 comic. The cloaked creature, sometimes called “Mistress Death” or “Lady Death,” is typically involved in storylines set in space. Death is essentially immortal and wields immense power, including the ability to manipulate time and matter.

Death's paths have crossed with the likes of Mar-Vell, members of the Fantastic Four, the Grandmaster, and others. However, she is most famous for being the object of Thanos' unrequited affection. In the comics, the whole ordeal with the Infinity Stones was an attempt by Thanos to woo her.

At the moment, it seems extremely unlikely that the MCU incarnation of Death will have any ties to Thanos, considering his saga is already over. There are also many witch mysteries to be solved in “Agatha All Along” – such as Rio’s whereabouts during the final trial.

What do we know about Rio Vidal?

Agatha (Kathryn Hahn) (left) and Death (Aubrey Plaza) have an unresolved business.

(Chuck Zlotnick / Marvel)

Ever since she burst into Agatha's murder mystery hallucination, it's been teased that there's more to Rio than meets the eye.

Agatha and Rio have history. The conclusion from the start was that Rio and Agatha were caught up in the past. And even though the relationship may have ended centuries ago, they are clearly still attracted to each other.

Rio can't kill Agatha (even if she wanted to). If her comments in the heat of the moment are to be believed, Rio is “not allowed” to kill Agatha, while Agatha cannot kill Rio or absorb her powers.

Rio speaks Spanish. When Rio said goodbye to Agatha for the first time, her parting words were “te veo.” It could be a nod to Plaza's legacy or something that plays a role in the remaining episodes of the series. Ya veremos.

Rio hates ghosts. When Agatha's mother appears in Episode 5, Rio explains that she hates ghosts. But maybe she just doesn't like her ex's mother.

Rio is the Green Witch. Rio explains that she is “less A green witch, more The Green Witch” when she meets Agatha’s coven for the first time on Witch Street. This suggests that Death in the MCU could have control over the circle of life rather than just ruling over Death. Could regeneration, renewal and/or rebirth be waiting for us at the end of the Witch's Road after all the dying along the way? To find out, viewers will just have to wait for Wednesday's Agatha All Along finale.