At the end of "Reality Bytes" Kara Danvers/Supergirl (Melissa Benoist) and Alex Danvers (Chyler Leigh) got some terrible news. The long-missing Jeremiah Danvers had been found dead, apparently from a heart attack inside his apartment in Peru. It's devastating for the Danvers sisters, but it turns out that Jeremiah's death wasn't exactly from natural causes and in Sunday night's "Deus Lex Machina" it's revealed exactly how he died as well as who was responsible for it.
Spoilers for Sunday night's episode of Supergirl, "Deus Lex Machina", below.
Earth-Prime's Eve Tessmacher (Andrea Brooks) played a major role in "Deus Lex Machina". It turns out that, on Earth-Prime, she's unwillingly a spy and assassin for Leviathan, having been forced into their service when they murdered her father and threatened to harm her mother if she resisted. Lex Luthor (Jon Cryer) decides to use her predicament to his advantage, offering to help free her from Leviathan if she will work for him instead.
Lex lavishes praise and attention on Eve for her efforts and, as she continues to help him carry out his complex master plan to take down Leviathan, he also pledges to find the man who murdered her father and presents her with that information. The man who killed her father, according to Lex, was Jeremiah Danvers. He says that Jeremiah is a Leviathan operative currently undercover with an NGO in Peru. He also gives her a vial of deadly poison so that she can avenge her father.
Eve does go to Peru and kill Jeremiah, but it turns out that Eve was just a puppet for Lex. Jeremiah didn't kill Eve's father. Lex simply had her kill Jeremiah because he's Supergirl's father and since he now has video of Eve killing him, he can use that as leverage to conscript Eve into working for him even after he reveals all the ways he's manipulated her.
The revelation is one that speaks to just how dastardly Lex really is, but it also offers a bit more meaning to Jeremiah's off-screen death. Having the Danvers sisters' father die in such sudden way seemed a little too easy. Now that we know that Lex was truly behind things, it offers even more opportunities for conflict between Supergirl and the villain, should the truth every come out – and given how bold Lex has gotten, it seems like something that will eventually come out.
Supergirl airs Sundays at 9/8c on The CW.