The Black Heart in ‘Agatha All Along’ may not be who we thought it was

The mysterious Black Heart; the last member needed to join Agatha’s coven to walk the Witches’ Road. We thought we had a pretty good idea who the Black Heart was, but Agatha All Along’s sixth episode has thrown a wrench in our hypothesis.

In Agatha All Along’s second episode, viewers saw Agatha and Teen (now revealed to be Billy Maximoff) run around trying to recruit witches so they could walk the Witches’ Road. Their first stop was Lilia Calderu, a divination witch whose powers allowed her to write a list of potential names. The list included Alice Wu-Gulliver, Jennifer Kale, Lilia herself, and one final member—only there was no name, just a drawing of a black heart.

Spoilers ahead for Agatha All Along episode 6.

At the time, Agatha and the rest of us assumed that the black heart referred to Rio, a Green Witch with whom Agatha is well acquainted (wink wink). She has referred to having a black heart multiple times in the series; that, and her implied romantic connection to Agatha, made her the perfect fit—until now.

Is Billy the Black Heart?

In episode 6, “Familiar by Thy Side,” we saw the last three years of Billy’s life, including his relationship with his boyfriend, Eddie. The pair are ridiculously cute together, with Eddie accepting Billy’s unique circumstances with support and love. While the two are texting one another, Eddie sends Billy a message saying, “You are my [black heart emoji].” This has fans wondering if we were wrong about Rio being the Black Heart. Billy is on the Witches’ Road, after all.

Another clue is that, due to the sigil Lilia placed on Billy when he was still William Kaplan, she would not have been able to write his name down on the list. Instead of writing his name, Lilia wrote something that symbolized Billy; in this case, a black heart. As far as we know, nothing was stopping her from writing Rio’s name down on that list, which further points to the fact that the Black Heart is Billy, the one person whose name she could not write.

Who, or what, is the Black Heart?

In Marvel Comics lore, Black Heart, or Blackheart, is the son of Mephisto. Mephisto is a character whose appearance Marvel fans have been manifesting for quite some time. Before it was revealed that it was “Agatha all along,” many assumed that Mephisto was behind the abnormalities in Wanda’s Westview in WandaVision. It was a fair assumption. In the comics, Billy and Tommy’s bodies are created by Wanda’s magic, but their souls belong to Mephisto.

Could Marvel be merging these characters into one? Could Mephisto arise and claim that Billy is his son, Blackheart? Could Rio still end up being a gender-swapped Blackheart? Where was she in episode 6, anyway? So many questions are still hanging over both characters. Let’s just hope they are all answered by the end of the series.