Satella (サテラ) is the Witch of Envy responsible for the Great Calamity 400 years ago who is currently sealed underneath the Pleiades Watchtower. In reality, the Witch of Envy is a separate personality, born when she took in incompatible Witch Factors. Satella formally debuted in Arc 4 as a supporting character, whilst the Witch serves as an overarching antagonist throughout the series.
She possesses a yet-unexplained connection to both Subaru and Emilia, and was also the one who gave Subaru Return by Death. Throughout the series, the Witch silences Subaru whenever he attempts to talk about his ability. Satella herself did not debut until Arc 4, where she and the other witches helped Subaru accept himself and change his views on Return by Death.
Satella has a thin body with long silver hair and purple blue eyes. When Subaru encountered her at Echidna's tea party, she wore a black dress made of shadows that seemed to wave in accordance with her heartbeat. Initially, he was unable to see her face because of a black shadow covering her above her neck, which was created out of his reluctance to accept her, however he later accepts her and becomes able to see her face, mentioning afterward that she looked exactly the same as Emilia.
Contrary to popular belief, Satella and the Witch of Envy are separate personalities, formed when she took in incompatible Witch Factors. The two personalities tend to fight each other. Both personalities love Subaru, though the Witch of Envy personality is much more aggressive about it, while Satella is much more reasonable and cares deeply about his well-being.
400 years earlier, Satella absorbed Envy Witch Factors she had no compatibility with, resulting in the creation of her Witch of Envy personality. However, this alternate personality was not the reason for her subsequently going out of control and killing countless innocent people and nearly destroying the world. Despite the efforts of many, including the Dragon, the Sword Saint, and the Sage, Satella was unable to be killed and was instead sealed in a shrine that is watched over by Shaula.
Authority of Envy (嫉妬の権能 Shitto no Ken'nō): Satella is able to use the Authority of Envy.
- Although the abilities of the Authority of Envy haven't been revealed, in the Web Novel, Minerva mentioned during the Witches' Tea Party that Satella might direct her jealousy (妬み Netami) toward her if she stepped in between her and Subaru, suggesting that it's something that affects people remotely.
Shadow Control: Satella is able to control shadows, though it's unknown whether this is a part of her Authority of Envy. They erode or destroy all life and matter around her as well as taking abstract things like thoughts and sometimes even memories and mixing them together. It's also shown that she's capable of manipulating someone's feelings and emotions, amplifying or fabricating them to her own liking. In Arc 7, Beatrice suggests that her Shadows might have something to do with Shamac as the're able to separate a person from their mind, similarly to how Shamac works. In addition, she was the one who teleported Subaru, Rem and Louis to the Empire.
- Satella is able to create shadow tendrils which she uses to capture, impale and decimate her enemies. The tendrils are strong enough to hold transformed Garfiel in the air and incapacitate him. She is also able to slip the shadows into someone's body through wounds and disperse them outwards, effectively destroying the opponent from the inside out. In some instances, she can also be seen creating hands from her shadows, gripping Subaru's heart whenever he speaks about his ability to anyone who isn't her.
Time Manipulation: Satella does have some degree of control over time, as she either manually or enabled Subaru to turn back time whenever he dies. It is unknown whether this is part of her Authority of Envy or a completely different ability.
Yin Magic User: According to Beatrice, the Witch of Envy is able to use Yin Magic. She presumably used a very advanced version of Shamac to split space and teleport Subaru, Rem and Louis to the faraway lands of the Empire. Also, according to Beatrice, the spell was a clump of Yin Magic aching to Shamac that was given a direction.
- According to the author, the meaning behind Satella's name will be revealed in the final arc.
- According to the author, Satella lacks common sense, and the situation is so serious that her dictionary doesn't even have the word common sense.
- According to the author, if Satella and Reinhard van Astrea were to fight it would end in a stalemate as she wouldn't be able to land a finishing blow whereas Reinhard couldn't bypass her immortality.
- In the anime, Satella received a redesign by Otsuka Shinichirou.
- Subaru has said the exact same phrase he said to Emilia in episode 1, to Satella at the end of the tea party, with the exact phrase being "I will save you no matter what". In Japanese:-『俺が、必ず――お前を、救ってみせる。』
- The author once stated that Satella is the second tallest of the witches.
- Satella is similar to the Latin word Satelles meaning "attendant, follower, servant, or guard." This is also the root word for satellite.