Elena Aoki

Elena Aoki (青木 江麗奈, Aoki Erena) is the older sister of Clair Aoki who turned into a monster and killed their parents.

Appearance
Elena is a fair-skinned young woman with short dark blue/black hair, red eyes and a rather slim and more modest physique compared to her younger sister.

She is often seen wearing a brown hat.

In her monster form, she turns into a gloomy large female ghost-like creature with long hair.

Personality
Elena is an emotionally unstable person who has a crush on Shuichi Kagaya, which makes her act shy and timid around him, but at the same time exhibits a selfish, murderous possessive attachment to him.

She was the one responsible for turning Shuichi into a costume-like monster with the full intention to "become one" with him by entering inside him much as Clair does.

Psychotic and deranged she is able to drastically change her emotions at a mere flip, acting with murderous intent at her would-be attacker, but calming herself down as soon as she realized it was Shuichi (in truth Clair inside him) and even apologizing for what she had done to him and willing to be killed by him in revenge. This all changed as soon as she heard a girl voice inside of him as she all too easily snapped and beheaded Shuichi to know who was the girl who was in "her place".

A lunatic and a murderer, she has no qualms about killing her own parents, feeling nothing about this deed. Not only that, but both Shuichi and Clair realized through their enhanced sense of smell that Elena has committed a terrifying number of murders that left both of them frightened and thinking that she was indeed a true monster in every sense of the word.

For all her emotional insanity, she does still have some lucidity left as she still feels love for her younger sister whom she spared after she killed their parents, later claiming she did it for Clair's sake and even giving her a coin she knew could be useful to her. When seeing that Clair was the girl inside of Shuichi she stopped her aggression and gave her another coin before leaving.

Plot
Elena had found a coin and used it to get her wish granted where she later turned Shuichi Kagaya into a monster.

When Shuichi and Clair Aoki finally find her, Clair being inside of Shuichi tried to kill her, but Shuichi intervened and made her miss her gunshot. At that moment, Elena transformed and they froze in fear, but Elena quickly started to apologize to Shuichi. They went somewhere more private and Elena wondered if Shuichi learned about her from the Alien and that she knows why he is there to kill her, as she was the one that turned him into a monster. Shuichi having no memories of this or Elena didn't understand what she was saying. But Clair then spoke from inside Shuichi and upon hearing her voice, Elena transformed and lost herself in angry ripping Shuichi's head to see who was inside. The moment she did it, she realized what she had done and started apologizing. Seeing her sister inside, she wondered why she was there and after Clair asked about their parents, Elena explained that their father was a corrupt politician and their mother had young lover and that as Clair had said she wanted to kill them, Elena just did it for her, as she was no longer weak and needing protection. She gave Clair another coin, telling her to use it wisely and then received a phone call and left.

Power & Abilities
After getting her wish granted, Elena can transform into a gloomy ghost-like creature with long hair, strong enough to easily rip off Shuichi Kagaya's head. She seems to have the ability to transform into an ash-like matter to form her monstrous shape.

Her presence seems to be quite overwhelming as Shuichi felt terrified purely by being touched by her, reasoning he was not at her level.

Shuichi Kagaya
Elena was Shuichi's girlfriend who erased his memories due to them getting in the way and the would end up becoming an obstacle for her and would result in making her look weak, In the anime, she erased his memories to not remember and avoid Honoka at all costs. Soon after Chihiro Yoshioka tells her, she cried and wants to hide her feelings from her team.

Clair Aoki
Clair is Elena's younger sister.

Etymology

 * The name Elena means "bay, inlet" (江) (e), "beautiful, lovely" (麗) (re) and "apple tree" (奈) (na).
 * Elena's surname Aoki means "blue, green" (青) (ao) and "tree, wood" (木) (ki).