The Quest for Immortality - Chapter 13: The Oil Lamp

It is eight or nine years for her to meet her first love again. In the gas station of highway, she sees him walking from the grocery store. She looks at him, not believing what she sees and asks, ‘Do you still remember me?’ He looks at her, with a bottle of mineral water in his hand, and says peacefully, ‘Yes, even if you became ashes.

- Description from Novelupdates

In a world where magic is a science, Siobhan is a genius.But even geniuses need schooling.When Siobhan stumbled into the theft of a priceless magical book, she thought her dreams of becoming the world's most powerful sorcerer were destroyed.But then a mysterious spell changed her life forever...Siobhan is now wearing the body of a strange man and has a new identity—Sebastien. With a new chance for a new start, she allies herself with a local gang—secretly a revolutionary party funding itself through crime. Now, she is bound by vow to repay them in magic and favors. But as Sebastien's reputation begins to bloom, and Siobhan's old enemies still lurk in the shadows, she quickly realizes that the secrets of this world are deeper and darker than she ever could have imagined.Forced to juggle the two sides of her double life, Siobhan is determined to uncover the truth and take control of the name they gave her - The Raven Queen.

[I was reincarnated as an F-class Hunter.

…it’s a problem because they don’t treat me that way.]

Another entry in what you can call the Proto Harem Series: the books written before the Harem Series that take place in the same world.

It’s about a swordswoman whose student is captured, so she goes to rescue her.