Mine is actually a bit disturbing and dark, per se. It's more in the lines of a graphic novel like "watchmen" or "The Dark knight", each of the sailor scouts dealing with a lot of issues while at the same time dealing with certain villains of my creation. Each of the following sailor scouts have their own issue(s) or volumes. With the all the guardians going their separate ways after college.
Dealing with trying to get her relationship with Tuxedo Mask in order, getting engaged/married, raising Chibiusa , death in the family, deciding whether to continue fighting Sailor Moon, debating on passing the torch to someone to fight as sailor moon, suffer a miscarriage and can't have more children, her relationship with Luna starts to deteriorate.
Gets into medical school, meets Ryo again for the first time since the end of the series and forms a relationship, her father gets involved in the picture, witnesses death when a fellow classmate dies in her hands, father knows she's sailor mercury, questions the concept of love as a whole, questions herself constantly, doesn't express love, becomes a doctor, contemplating whether daughter should become a sailor guardian
Becomes head priestess at the shrine, grandfather dies, Starts having monogamous relationships, causes the accidental death of a little girl, guilt trip, parents remarry to other people, targeted for death for possession of the shrine, declares a life of chastity, temporary Alcoholic, lawsuit against her by tthe city of Tokyo as Mars, debates on either living on earth or her castle,
Jupiter: discovers more on parents death, works for the military, became part of a military project, lives by herself, can't control he powers as she used to, helps government fight against the paranormal, retires from the military after getting married, opens a flower shop and bakery, dealing with motherhood, past catches up with her, trains daughter as a sailor guardian, wants to protect those closest to her.
Works for the police, arrested as sailor venus, moves back to England, in an abusive relationship, sent to the hospital, strained relations with Artemis, becomes a pop musician, gets married then divorced, temporary quits as sailor venus, kills an unarmed criminal, becomes most wanted, goes on the run, becomes a single mother, retires as pop idol, parents get divorced. Considers abortion at one point, deals with body issues, more self conscious about her body, becomes a spokeswoman to teenagers about body image.
More on her background, backstory before became Sailor Pluto, how she gained her powers, adjusting to life as a normal civilian
Becomes a concert violinist, gets married to Uranus, develops drug habit, questions being a sailor guardian altogether, wants to start a family, has to take care of Saturn after family passes away, finds out she has cancer.
Starts going out with Neptune, is in the military special forces, can't come out to family, questions identity, develops PTSD, cheats on Neptune, goes to jail, Starts fighting for money, starts raising awareness of LGBT rights
Tragically loses family, has amnesia, can't control her powers, doesn't want to be a Sailor Guardian, wants to live a normal life, goes to live with Neptune and Uranus, lives in an orphanage for a while, starts messing around with the black arts, dies and comes back to life.
It may have questionable material and may be dark at times, but it's the fact that they're real problems which makes it interesting and addicting to read. Some characters may have more than one volume considering the source material.