The protagonist, Noriyuki, lost his young wife to an illness a few years ago. In the midst of despair, he met Haruka who then supported him.
Afterwards, Haruka's existence meant a lot more for Noriyuki, which led him to opening up about his late wife and proposing for marriage, to which Haruka accepted.
Their happy married life started, with Noriyuki working at a company and Haruka working at the university she graduated from.
One day, the younger brother of Noriyuki's late wife, Rikurou, who he hasn't been at contact with for a long time, appeared before him with a DVD. Inside the DVD is a video of Haruka being fucked by Rikurou, with her defloration scene on tape as well. When he asked Haruka about it, she said it was a folly of her youth.
However, Noriyuki saw it as a mere thing of the past and not something they should worry about, and that even he himself had another woman in the past. Once again confirming their love for each other, the trouble was gone.
Or so he thought...
The protagonist, Ayano Taiki is a physics teacher at a high school. In school, he also acts as an advisor for the Astronomy Club which is a club consisting of only two members, sisters Aimi and Yumeno. He is living a peaceful and fulfilling life.
One day in July, Taiki is invited by the sisters to come with them to have a "training camp" in their home village they are returning to for summer vacations. Since he has no parents or relatives and as such, nothing to do, he gladly takes the sisters' invitation
When summer vacations start, he arrives at the countryside where the sisters wait, there he meets their cousins Saki and Chieri and receives a warm welcome.
This will be a great vacation, is what Taiki thought... But what awaited him, were quickly-passing days full of obscenity.
In the past, this island was a fertile and peaceful kingdom ruled by a royal family. The coat of arms was carved in the likeness of dragons and angels, the protectors of the kingdom. The kingdom's history was said to span several thousand years, the faith of the denizens in the reigning king and queen strong and the entire island enjoyed the embrace of peace.
However over a decade ago, demons suddenly appeared and attacked the kingdom. The Knightly chapters were annihilated by the demons' powerful magic. The King and Queen were killed and the capital was felled by flames in just one night. The archdemon who attacked the kingdom styled herself the "Progenitor Demon".
The archdemon proclaimed the island would be ruled by her loyal subordinates, the five "Witches".
Now, the island is under the witches' control. The five witches are beings possessing great power, the island's denizens are cowed by the witches' intimidating powers. The witches have ruled for over a decade, but none of them age nor weaken. If anything their powers continue to grow. People think that making a contract with the Witches and the demons would allow one to gain eternal life and magic powers. Those who opposed these beings who were effectively demons found their numbers dwindling, until the island's denizens resigned themselves to the witches' cruel reign.
Gilbert, a man who hunts demons for a living yet has command over demonic powers, ventures forth onto Regulus island to hunt the demons who have possessed the Five Witches as well as the Archdemon who dominates them.
What fate awaits him...
Hayate’s parents departed on a cruise around the world, leaving him and his three sisters Haruka, Fuyuka and Natsuki to take care of the house. He thought that these three months would pass without much problems, but his sisters decided to take advantage of the situation to draw even closer to their dear little brother.
They had once made an agreement to not make any moves on him before he became a working adult, which was reaffirmed shortly after their parents’ departure. However, Natsuki gave a daring kiss to Hayate while he was sleeping to cheer him up from the strange dreams which he had been seeing. Hayate began to see her as a woman, and this incident was seen by Haruka. Despite Natsuki’s claims of innocence, the other two sisters became increasingly impatient knowing that Natsuki was one step ahead of them. A passionate summer lies ahead for Hayate and his sisters.
The protagonist, Naohiro, and his wife Risa have been married for 4 years. Their married life is smooth sailing, and the good relationship between them is enough to be envied.
Except for one feeling born from Naohiro's heart...
It all started with a small incident. One night, when the couple was happily drinking together, Risa talked about her ex-boyfriend, and after the conversation, Naohiro felt a strange excitement.
Feeling weird, he searched the internet about it, and while doing so, realized that he does indeed have "that" fetish.
However, he can't possibly tell that to his beloved wife, but the more they find happiness with each other, the more stinging sensation torments him from within.
Then one day, one of his juniors back in school, Tsukasa, consulted him about something...
With beautiful flowing black hair and good looks, on top of a calm personality and polite speech, Maho is a well-raised lady no matter how you look at it. However, behind that exterior lies a true side that no one could have imagined: she is actually a avid ero doujin author!
Koutarou ended up moving into the apartment that she managed and quickly discovered the secret that she had tried to cover up at all costs. She was horrified that her secret was out, but contrary to her expectations, he accepted and supported her dream of being a creator. So, she made a once-in-a-lifetime request to him in order to produce the most amazing work:
“Could you provide me with erotic reference materials?”
Thus, he was recruited to help with countless ‘material gathering sessions’. How will the ero manga that they worked on together turn out?
