Mitsuki Amanogawa

Mitsuki Amanogawa is the younger sister of Kouki and was the founder & president of the Soul Sisters.

Appearance
Mitsuki is a beautiful young girl with long glossy black hair and almond-shaped eyes.

Personality
Mitsuki is a strong-willed and rambunctious girl who is mischievous as she would often pull pranks on those that she holds a grudge over, such as Hajime Nagumo and Ryutarou Sakagami. She is also a bit childish, spoiled and quite delusional, especially with her obsession for Shizuku.

Background
Mitsuki had known Shizuku since elementary school and was very fond of her. This eventually lead her to founding the Soul Sisters that was full of female students that also shared her fascination of Shizuku. Unfortunately, Shizuku and her older brother Kouki, as well as their entire high school class, were summoned to the alternate world Tortus. Fortunately, Shizuku did come back, along with the remaining students of her class, but Shizuku was in love with Hajime Nagumo, and not Kouki.

Chronology
Upon the Returness' return to Earth, Miya along with her parents Seiji and Mitsuki Kouki enter the house he started to explain the circumstances of their sudden disappearance until his friend Ryutarou Sakagami while he was in his werewolf form, stormed into the house after they panicked when he transform. Seiji fainted, Miya went on a rampage with a knife, and Mitsuki wetted herself. Kouki immediately knew it was Ryutarou and calmed Miya down and made Mitsuki sleep, all before he punched his friend in the face. After the mess, Kouki's and Ryutarou's families held a meeting in order understand what happened.

About nine months after Shizuku and the other students returned to Japan, demon-worshipping cultists attacked the students, as well as anyone affiliated with them, including Kouki's family. They were able to keep the cultists at bay thanks to the barrier artifact that was provided to them by Shizuku's husband Hajime, but they still kept attacking their home. Mitsuki phoned Shizuku and asked for her help (as well as using the attack as an opportunity to see her again), but she was unable to come due to having to fend off cultists that were attacking her home as well. Mitsuki and her family were eventually saved by Kouki's best friend Ryutarou. Mitsuki then invited Ryutarou to the backyard in order to punish him for preventing Shizuku from visiting her due to his timely arrival. Ryutarou was aware of her intentions and fled his house as fast as possible.

When Shizuku and Hajime were on their way to do a wedding-themed photoshoot as a favor to Mitsuki's mother, they were suddenly approached by Mitsuki and the other Soul Sisters just as they arrived at the venue. They attempted to attack Hajime in order to make him unable to do the shoot. Hajime easily repelled the Soul Sisters after he grabbed one of them and forced her to drink a laxative before tying her pigtails up and writing on her face with a permanent marker as an example of what would happen if they tried to challenge him. As the Soul Sisters were prepared to leave, Mitsuki and her fellow Soul Sister, Manami suspected that the student actually liked being bullied by Hajime, much to her denial.

Kouki Amanogawa
Mitsuki was disappointed at her brother for not being able to marry Shizuku Yaegashi and becoming her future sister-in-law, which is a result for her to call him an idiot and Kouki doesn't know of his sister's dark nature. Although she criticizes Kouki for his faults, she still loves her brother very much.

Manami Endou
Her fellow Soul Sister. The two of them often hang out together.

Kouhai-chan
Her fellow Soul Sister. Mitsuki suspects her having a crush on Hajime.

Shizuku Yaegashi
As the founder of the Soul Sisters, Mitsuki idolizes Shizuku. Shizuku finds Mitsuki and the Soul Sisters to be annoying when they try to break her relationship with Hajime Nagumo, but she still cares for Mitsuki due to their past history.

Hajime Nagumo
Like the rest of the Soul Sisters, Mitsuki despises Hajime and wants to end his relationship with Shizuku Yaegashi, which has always ended in failure.

Ryutarou Sakagami
Mitsuki has known Ryutarou since she was born and would frequently torment him. Ryutarou could never go against Mitsuki due to how close he is with her family.

Etymology

 * The name Mitsuki means "beautiful" (美) and "moon" (月).
 * Mitsuki's surname Amanogawa means "heaven/heavenly, sky, imperial" (天), "this" (之) and "river, stream" (河).