I will Live as a Marquis Son, So Obsession is Difficult

Hidden from the prophecy, Runedeluz Esté, the daughter of the Marquis, was raised as a ‘boy.’
Rune, as the sole heir of the Esté family,
applied to the academy to become a Sword Master following her father’s footsteps. However, the Marquis consistently opposed it, isolating her from the world.
The seemingly forever closed gates opened, revealing an unfamiliar guest.
“It’s been a long time, Runedeluz.”
“…Do you know me?”
In her memory, an absent figure, someone knights would admire and idolize.
The leader of the Dark Knights and the commander of the Empire, Kylian Herais.’
“A closed door is ultimately just a wall. If you wish, I can be your key.”
He suddenly appeared, disrupted her daily life, and then left.
He sent her the academy recommendation letter she had longed for.
And upon entering the academy and ranking first, he declared that she would be his squire.
“Runedeluz Esté. I appoint you as my squire.”
Kneeling on one knee and briefly kissing the hilt of his sword, Rune raised her head.
“I pledge with all my heart and faith, staking my life and honor.”
It was an honorable oath to become a knight solely for him.
* * *
“You always make me regret. And you make me scared.”
Meeting again after three years, Kylian had a sharp face that seemed a bit more haggard.
Her lips, which had shared an oath with a kiss on the sword hilt, were now closer to Kylian’s lips, as if they were about to touch.
“I’m giving you a chance to escape me now.”
“…Do you mean to say that you want me, a man, now?”
Rune trembled.
She wanted to indulge in the emotions she had ignored for so long, even if what he desired was the false image of her as a man.
And as if conducting a verification ritual, he answered desperately.
“Yes, I want you.”