Toaru Majutsu no Index - Volume 15, Chapter 5: Defeat the Person with the Strongest Black Wings. Dark_Matter.

A teenager who unexpectedly gets transported to the modern world from ‘the world of the immortals’ . He finds himself in the body of an ordinary guy. He wants to go back to his world and for that, he will have to practice to get stronger and investigate the reason why and how he crossed through to this world.

- Description from Novelupdates

In a Fantasy world in which a young girl with the Divine Protection of the Hero battles against the Demon Lord. In that world, Red, the elder brother of that young girl Hero, possessing the Divine Protection of the Guide which only grants a high initial level, fought in the initial party of the Hero.

It has been more than ten years since he was transported to another world. The protagonist Deris Fahrenheit, who has became a magician with special circumstances, was freely enjoying his life in this world. However, a girl appeared before him and asked him to make her his disciple. That girl seems to be a transported person――

It’s a story of him who becomes the girl’s teacher and trains her to achieve her revenge (?) in otherworld.

“If I really want a woman now, I hope it is you!”

In the doctor’s office, Dr. Fu, who has always been proud and reserved, restrain his breathing and giving an invitation to the patient in front of him.

“Although you are very handsome,…”

“I can be responsible for you afterward!” Facing the patient’s embarrassment, Dr. Fu suggests a very responsible suggestion.

Life is not easy, she is careful at every step, attacking those who frame her.

He helped her everywhere and cherish her to the extreme.

It is said that Dr. Fu is not powerful and impotent.

Who would know that he is powerful and skilled in bed.

One night, he pressed the beauty under his body. “Doctor Fu, how can I thank you for helping me?” He caressed her small waist and made a low-key announcement. “The dowry should be prepared!”

Dr. Fu said: Happy to meet you in my lifetime!

Miss Gu said: In my lifetime, please treat me kindly!

- Description from Novelupdates