Princess X - My Fiancee is a Monster Girl?!

"The human heart is but a vessel for pain."

That's what someone once whispered―a voice laced with loneliness, whispering directly into the soul. It's an indescribable sadness, a love just beginning to bloom. It becomes an invisible pain that pierces the heart. And that's what makes up life: a cyclical series of highs and lows.

Tachibana Sai was born without the ability to feel pain in his heart. He spends his days eliminating any seeds of malice that sneak up on his sister, the one person he treasures, without drawing attention to himself.

Sick of the never-ending monotony he lives through, he chances upon a meeting with Benio Matsuri, a young girl whose aloof demeanor resembles that of a beautifully crafted doll.

For the first time in his life, he encounters a heart-piercing sensation―that of falling in love.

On the edge between day and night, in a twilight world where the dead and living mingle, stands an apartment building called Maison sans Nom, which is home to a group of boys and girls.

A ruthless boy who knows no pain in his heart.
A lonely girl without any friends.
A friendly girl who struggles to make connections.
A prickly, ambitious girl who is keen to be of help.
A boy who loves his own cute self above anything else.
A mess of a woman who tries to solve everything through brute force.
And a boy with a tender heart who knows no pain in his body.

This ill-assorted group of residents, hands stained with blood from battling the supernatural Maledicts, shall encounter the hearts they never knew and begin nurturing their souls.

The human heart is but a vessel for pain.

To protect this pain akin to love... To gently break the world apart, piece by piece... Even if it means abandoning humanity. That's why the heart is but a vessel for pain.

For life blazes brilliantly, while the heart goes around in an endless cycle.

As a reserved and unassuming university student in snow-bitten Hokkaido, the personal tragedy which visited Honoka Asakawa would lead to her experimentation in a magical art thought long-lost — blood magic. Unexpectedly able to visit the sealed world of Meiji-era Sapporo, Honoka's quickly taken under the wing of the cheerful and bright Lady Yasue, a powerful mage who's remained in this gilded cage for a century.
 
As their feelings for each other develop, the true repercussions of Honoka's first steps into the secret world of magic and mages are only just starting to play out, eventually leading to catastrophic consequences.

In this game, you play as Fujita Hiroyuki, a high-school student who seems to have more interest in romance than in his studies. In his school there are several pretty girls, and his goal is to be nice to one of them, to make the right decisions when talking to her, and ultimately to win her heart.
 
Remake of the original PC version featuring a completely revised script, with some of the heroines having completely different stories as a result, full voice acting for all characters except the protagonist, new art, and mini-games.

In a future over one hundred years hence...

All the people in the world have awakened to unique abilities called 'Dunamis'. As these special powers become rooted in people's everyday lives, their value system changes, and those who lack powers are the ones who are treated as strange. With the passing of the ages, the environment has changed completely, while society has greatly regressed. The overall population of mankind has diminished as well, and most of the world is made up of wastelands and greenery dotted with the weathered ruins of the world before.

The City of Raillore.

With brickwork buildings like those of the Middle Ages, developed over land graced with lush greenery and rivers. With the concept of nations gone from the world, Raillore exists as something of a self-sufficient commune. The Order of Security and Regulatory Knights - AKA the Regulatory Corps - serves as a government organization in charge of handling crime prevention and other tasks that require force of arms.

But things begin to change as odd incidents take place, one after another...

Those possessing abilities different from those of Dunamis begin to appear. The people fear this power and the phenomena it causes, and those capable of it are designated as ‘Errors’. The sudden appearance of these Errors is regarded as a disease, and the handling of Errors is placed under the jurisdiction of the Regulatory Corps. As people tremble in fear of the vicissitudes of the changing times, there are those who try to open a way to the future with their own strength...
 

Uchihama Academy has seen an increase in enrollment in recent years and as a result, a new school building will be constructed. The story takes place during the final school festival in the old school. All the club leaders decide to give it their all to make this the best school festival. Sou is a member of the notorious astronomy club, which basically solves the various issues in the student council's place.

On one day, he stays in the school late at evening because he got slightly injured by the judo club and is healing his wounds in the infirmary. Suddenly, the building shakes. Shocked, he runs up the stairs to where the shaking seems to have centered, and there he encounters a mysterious naked girl, who at first appears to know him. On the next day this girl, Yui, seeks out the astronomy club, expressing her desire to join.