Eridna

''This page is about the Artificial Spirit. For the Witch of Greed, see Echidna.''

Echidna (エキドナ), commonly known as Eridna (襟ドナ), is an Artificial Spirit created by the Witch of Greed, Echidna, who is currently in service of Anastasia Hoshin. First introduced in Arc 5, she later plays a pivotal role in Arc 6.

A spirit sharing its name with her creator, the Witch of Greed, she met Anastasia by pure chance. After Julius had his name eaten in Arc 5, Anastasia allowed her to possess her so she would not forget him. In Arc 6, she guided Subaru and his companions to the Pleiades Watchtower. In the arc's climax, she gave Anastasia her body back, causing her to forget Julius but also allowing the two to start over.

Appearance
Echidna takes the appearance of a white fox with snow white hair and sharp black eyes, though she usually takes the form of Anastasia's scarf.

Personality
Similarly to her creator, Echidna speaks, sounds, and acts just like the Witch herself, however she has no memories of her past aside from her name. Because of this, Subaru nicknamed her Eridna (Scarfidna). She's also shown to deeply care about Anastasia, going to extreme lengths to make sure no one would find out about their condition. During Julius' fight with Reid Astrea, Echidna forced Anastasia's soul back into her body so she could witness her knight's resolve and subsequent win over the First Generation's Sword Saint.

History
Whilst it is known that the Witch of Greed created Echidna, the exact purpose of her creation and what happened prior to her meeting Anastasia is unknown. However, Echidna states that she felt like the purpose of her birth was completed the second she was born.

Nine years before Natsuki Subaru's summoning, Mother tasked a former slave named Reisel with retrieving an object relating to the legacy of the Witches. The object in question was a fox-like artificial spirit created by the Witch of Greed roughly four centuries prior. Echidna met Anastasia eleven years before the story after finding her enclosed within a wooden box that had been delivered to her in some cargo. Due to her inability to make a contract with humans, Echidna ended up becoming Anastasia's consultant because she was intrigued by her.

During the events of Arc 5, Echidna was forced to take Anastasia over when she overused magic through her defective gate. She was unable to leave her body for a while, but eventually separated with her.

Abilities
Artificial Spirit (人工精霊 Jinkou Seirei): As an artificial spirit, Echidna lacks in certain ways compared to a normal spirit. She lacks the ability to contract with humans and it is difficult for her to use magic to defend herself with, and in exchange, she is skilled at concealing herself. She is also a low-consumption spirit.

Possession: In emergencies, Echidna can overwrite her existence onto Anastasia's Od, making her able to temporarily borrow her body, and by doing so, she can use the mana inside of Anastasia's body to use magic.

Magic User (魔法使い Maho Tsukai): Echidna can use Yang Magic while borrowing Anastasia's body.
 * Jiwald (ジワルド): Jiwald is a Yang Element magic that allows Echidna to fire heat rays from her fingers.
 * El Jiwald (エル・ジワルド): Echidna can fire several rays from her fingers which are then brought down in a claw-like motion.

Anti-Recognition (認識阻害 Ninshiki sogai): The mechanism which Echidna can suppress others being able to recognize her true form. This ability doesn't work on Anastasia herself due to her defective Gate.

Trivia

 * Echidna's name refers to 42355 Typhon I Echidna, 42355 Typhon's moon and a companion to a binary asteroid. In Greek mythology, Echidna is a monster who was the mate of Typhon.
 * Echidna is indirectly stated to be the second artificial spirit created by the Witch of Greed, Puck being the first and Beatrice being the last.
 * According to the author, the difference between Echidna and Eridna is the existence and nonexistence of a human heart.