First Stygian Diviner:Apocalypse - Chapter 40 The Measurement Room

Due to a mistake on his student’s part, a super Martial Artist had received a wrong class in an online game and had become a mage. He who was used to curbing violence with violence and using strength to subdue strength could only make the best out of his mistake. Taking on a new lease in life, he became a violent close combat mage. When strength and magic came perfectly together, a new gaming path had been opened by him!

I am Master Siwei, and I speak for arcane arts.
This is an era of heroes and heroines.
This is an era of great changes.
In the end, it will be an arcane era opened by me.

- Description from Novelupdates

Katori Nanatsuki transmigrated into the world of Bleach, becoming the younger brother of the original generation Captain, Katori Batsu'unsai.At first, he thought he had a reliable backer to cling to—but soon discovered that Katori Batsu'unsai was already gravely ill and didn’t have many years left to live.Fortunately, he awakened a Teacher System—as long as he taught, he could grow stronger.To gain the strength needed to survive in this world, Katori Nanatsuki became an instructor at the Shin'o Spiritual Arts Academy and inherited the Katori-ryu Dojo, dedicating himself to teaching and training students.【Muguruma Kensei completed swordsmanship training under your guidance. Reward acquired—Sword Technique: Crimson Tide】【Aizen Sōsuke completed Kidō training under your guidance. Reward acquired—Hadō #90: Kurohitsugi】【Kurosaki Ichigo’s power increased significantly under your guidance. Reward acquired—Schrift: “D”】Years later, Aizen Sōsuke suddenly appeared...(If you enjoy this novel and want to support me, Please join me on my page: [email protected]/MirnOuch)

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