Satu Järvinen’s fate inA Discovery of Witchesis tied to her choices throughout the show and how she views her powers, but this is all taken away from her in the series' climactic all-out magic war. After using Matthew as bait to bring Diana to her, the two havea dramatic face-offwhich results in Satu no longer being a threat.
Satu’s defeat is more satisfying in the show because of the showrunners’attention to developingcharacters inA Discovery of Witches. Rather than an outright villain, she is a weaver who shares some traits with Diana and easily could have been a great witch, if only she had made better choices like her light counterpart. As a result, what happens to Satu inA Discovery of Witchesis a key part of emphasizing the series' broader themes and message.

A Discovery of Witches Review: This Supernatural Romance Is Almost Bewitching
Sundance Now and Shudder premiere the UK series A Discovery of Witches, a sharp-looking, albeit occasionally cheesy supernatural romance.
Diana Spellbinds Satu In A Discovery Of Witches Series Finale
Satu Is Defeated By Diana In The Finale
In the TV adaptation of Deborah Harkness’All Soulstrilogy,A Discovery of Witches,Diana defeats Satu in a big face-off. Diana fights Satu and Benjamin to save Matthew. Satu uses illusion magic against Diana, but they are no match for her resolve. After she sees through them,Diana spellbinds Satu. Turning her attention to Benjamin, she weaves the final knot, whichTeresa Palmer inA Discovery of Witcheshad to learn with a choreographer. This ends his life. Meanwhile, Matthew’s condition deteriorates, requiring Ysabeau’s blood. He was urgently transported back to Sept-Tours.
(Satu) is a dark mirror to Diana…
Diana and Satu’s conflict is built over a long period in the show. InA Discovery of Witches,Satu is an outsider, ruthless and hungry for power, and a manipulative character. She allies herself with whatever villain is useful. Initially, one of these villains – Knox – is more powerful than her, which he proves in a torture scene. However, throughout the series, Satu develops her weaving powers to become a force to be reckoned with. She is a dark mirror to Diana, highlighted in episode 6 when Gerbert says,“There are two powerful witches here. One light, the other dark.”
What Being Spellbound Means For Satu’s Fate
Being Spellbound Inhibits Satu’s Powers
Diana has no choice but to disempower Satu. A weaver with no moral compass running amok is too dangerous. Diana makes a difficult decision spellbinding her, especially as she has been spellbound in the past.When a witch is spellbound, their powers are inhibited. Normally in theAll Soulstrilogy, when spellbound, this can only be undone by the witch who has cast the spell. Satu had the opportunity earlier in the show to follow the forces of good – Diana points out,“We could have been the greatest allies”– but her choice to compete with Diana is her downfall.
When spellbound, Satu’s power-hungry motivations are quashed. Throughout her character development, it is clear that while strengthening her self-weaving powers,she can follow either a light or a dark path. Driven by ambition and competitiveness with Diana, she chooses darkness – ultimately, her fate mirrors Knox because her over-confidence is her downfall. As Diana has seen what Satu is capable of, she is not likely to reverse her spell, meaning her dreams of proving she is the powerful witch of Meridiana’s prophecy are over.

Satu Has Much More Character Development In The Show
Satu’s character is one of several differences between Harkness’All Soulstrilogy and the TV adaptation, which ranks among thebest book adaptations. Several characters are changed to addmore detail and clearer motivations. Some of the changes are better inA Discovery of Witchesshow than in the books– Satu’s more complex character is one of the show’s advantages. In the books, she is more straightforwardly evil. The show does a better job of creating a more multifaceted character and portraying what can lead a witch down the path of either light or darkness. The showrunners intended to add more dimension to Satu this way:
“…We felt that actually, an audience would enjoy it even more if we track Satu through so we saw what led her to that point.”
viaRadio Times
The conflict between Diana and Satu uses parallels – for instance, they are both weaver witches who have previously been spellbound for their own protection, their powers hidden from them. The TV series explores what effect this could have on the characters and the trigger that leads them down either path. For Satu, this resulted inan unclear sense of self. She asks her“mummo”why she kept her weaver status from her –“You taught me everything, but not who I am. Why?”which highlights that she sees her powers as a cornerstone of her identity inA Discovery of Witches.