Valerian, The Legendary - Chapter 319 - Sudden Situation.

For decades, the brave warriors of the Northern Army fought to keep the world safe from the evil Silent Night. But when the fourth-generation leader, Jin Kwan-Ho is accused of colluding with the enemy, he is forced to disband the sect and commit suicide to protect his son, Jin Mu-Won. With no family and allies left, Mu-Won leads a dreary life under close surveillance… until a surprise attack from the Silent Night gives him a chance to escape to the mountains.

There, the young warrior trains to master the fighting techniques of his predecessors, before the mysterious disappearance of a loved one brings him back to the mainland. Follow Jin Mu-Won as he embarks on a journey to avenge his father’s death and take down the villains who threaten to plunge the world into darkness!

In the beginning, when they all thought that she was “he”….

ML #1: We will be brothers for life!

ML #2: This time I’ll reluctantly let you have the #1 seat.

ML #3: I will properly repay royal teacher!

ML #4: Ah Rong is my closest little brother, I trust him.

Afterwards…

MLs: I’m seriously such a fool.

MLs: What do I do, I think I’m gay. I fell in love with my bro/rival/teacher….

Afterwards….

MLs: I’m straight! As straight as steel!

Note:
MC is a girl crossdressing as a boy, she knows how to fight, and naturally possess the gold finger halo from the author.

All the ML(s) is the same person, 1v1, sc, HE

- Description from Novelupdates

This story revolves around a boy who was sent to a dark, mysterious parallel world in the body of his beautiful senior sister known as Lily. The lone girl ran into the night parade of a hundred ghosts the very day she arrived; seeking survival amongst the warrior’s dispute in a chaotic world, and forging her own demon sword! This is an unimaginable other world adventure!

An otaku with a hobby of masturbating was reincarnated as the son of a great mage.

As soon as he was born in this life, he vowed with a goal of embracing women till his death.

That said, when he became 20 years old, the Demon Lord which was sealed by his ancestors revived, and now it is his role to seal it once again.

And that demon lord is sealed in a tower dungeon that is rumored to be impossible to capture.

However, by an unexpected coincidence, he had found out that the Demon Lord is also one of him, a kindred spirit from within,

so he joined her instead and filled several traps in the tower dungeon, and thus they enjoyed a s*x spree with all the women coming over!