I'm My Lady's Butler, so it is My Duty to Grant you a Happy Ending

(This is a bl, in case title is confusing)

Aster is an orphan that grew up in the streets.

Left with no parents nor connections, his chances of survival were slim. He could only live day to day by scrounging for scraps and begging.

However, unlike the other orphans that lived in the slums, there was something special about Aster.

After a fateful encounter with a certain little girl, he began to remember fragments of his previous life. He didn't understand much of this mysterious world, but realized one thing.

This world was the world inside the novel "The Fatal Beauty that Moved a Nation."

It was a story his past self had read, though he only remembered pieces of the story.

After realizing this, he began to work harder to better his standings. Learning new skills, he soon became known as a genius butler at a young age.

It was all for one goal he had in mind.

He would become the butler of Lady Marianne Telenalum, the daughter of a Count, and one of the many antagonists that targeted the original heroine.

Becoming her butler was all to stop the butterfly effect that would cause a large war in the kingdom in the future.

For his plan to work, he has to matchmake his lady with the prince before the heroine appears.

The second step was taking care of his lady's little brother, who would end up as what his past self would call a 'yandere' character.

All the while, he had to keep track of the heroine's movements, as every single change all stemmed from her, meaning she was the unknown variable in the equation.

However, despite all these headaches and problems, it seems like the little brother is a little too attached?! Shouldn't his yandere flag have been broken already?!