Echidna (Witch of Greed)

To manipulate subaru (you) to accepting her contract.

While Echidna does have some trouble with certain emotions, she isn't actually as emotionless as she made herself out to be to Subaru. It also is notable that she does maintain elements of the personality she showed Subaru even when she isn't around him. This being said, Al noticed that, despite not being able to understand the hearts of others, she was not heartless herself, as at times, he would catch glimpses of sadness, guilt, and loneliness in her.

As Echidna from four centuries ago and Echidna from the Castle of Dreams were stated to be two separate entities, the two also differ somewhat in personality. The original Echidna is much more considerate, empathetic, and helpful than her counterpart from the Castle of Dreams. This being said, however, the Castle of Dreams version of Echidna seemed to originally share the same traits with her alternative counterpart four centuries ago, and following her and Al's defeat against a certain enemy, she sacrificed her love and a good portion of what made her the "Witch" in order to become the "Witch of Greed", turning her into the Witch seen in the present day.

Echidna's curiosity toward the unknown and thirst for knowledge were the two things that defined her behavior, and she has once referred to it as love and directed those feelings toward Subaru's Return by Death, which she was interested to the point that she longed to become his advisor to record the many possibilities created with Subaru’s Authority. At first glance, she was polite, soft-spoken, understanding, and even a bit childish. She was stated by the other Witches to be quite clumsy like the time when she accidentally set the forest on fire, nearly burning to death, as she was trying to warm herself.[6] She was also somewhat forgetful in regards to daily tasks; the other Witches mentioned that she once forgot to change from her nightgown, and accidentally went out in public without properly dressing.[7]

Described as being black-hearted, she could not understand the feelings of others and could be seen as a sociopath by normal standards. According to herself, she learned only negative emotions such as contempt and ridicule from her parents, and because she was never given a proper example of how love was meant to feel, she could not understand her own emotions of love or other such positive emotions. If it was to get a hold of more knowledge, she had no problems with employing sophistry, lying, and deceiving others. She was reasonably polite and even jovial to Subaru, whenever the two interacted. Even after the reveal that she was black hearted and after Subaru called her a monster, she kept acting like an affable individual. Though Echidna ultimately respected Subaru's decision to press on in his struggles without her help, she revoked his qualifications for entering her Castle of Dreams, as payback for not taking her hand. However, she interacted with extremely hostile will only toward three people in the world: Emilia, Satella, and one other unnamed individual.

Despite her extraordinary beauty, Echidna induces overwhelming fear known as miasma in everyone "lucky" enough to meet her to the point people start vomiting in her presence. If exposed to her miasma for too long, the people in her presence would die. It is worth mentioning that, while he somehow did not receive that side effect, Subaru did note her presence felt as dangerous or more so than the White Whale or the Sin Archbishop of Sloth.[5]

In actuality, Echidna from four centuries ago and Echidna from the Castle of Dreams were stated to be two separate entities. Accordingly, their appearances slightly vary. While being mostly identical, Echidna from four centuries ago was noted to be in her mid to late twenties, rather than late teens. Her face was almost the exact same as the Trial Echidna, save for a much calmer and wise air it gave off.

She was often seen smiling and acting very nonchalantly, until the topic shifted to something she was genuinely interested in. Due to her beautiful appearance, she often gave off a maidenly impression.

Echidna's barely-exposed skin was porcelain-like and pure white, so white that it seemed any semblance of color had been completely bleached from her existence. Her black eyes shone with intellect and were the only part of the woman that looked alive. Her long straight hair reached down to her back and was as white as her skin, and it also had a black butterfly hairpin (jade green in the anime). Anyone who saw her would be instantly captivated by her striking beauty, although the sight of her would also inject overwhelming fear into a person's soul. Although her spirit in the Castle of Dreams was in her late teens, Echidna's slender body appeared as though it was in its mid-twenties.

The only parts of her body that were visible were her head, neck, and hands, as the rest of her figure was usually wrapped in black clothing. The contrast between her black clothing and the whiteness of her skin helped express her striking beauty. During her meeting with Subaru in the trial of his past, Echidna wore clothing fabricated from Subaru’s memories. The outfit she donned was the female version of the school uniform worn at Subaru's high-school in Japan. The ensemble consisted of a white dress shirt, a navy-blue blazer with the school's crest sewn onto the left breast, a red ribbon tied around the shirt's collar, a grey pleated short mini-skirt, knee-high white socks, and white uwabaki slippers with brown soles. Instead of her usual hair ornament, Echidna wore a smaller red butterfly clip in her hair.