Toaru Majutsu no Index: New Testament - Volume 17, Chapter 2: Or Escape Provides a Counterattack - Social_Network_Slayer.

One day, a door to another dimension opened all over the world.

“Channel”

At the same time as the channel opens, different races appear on Earth, and mankind awakens its magical talent.

But…? Yoon Min-joon, was able to use magic long before the channel opened.

The forced escape of a reclusive loner who was once the only wizard on Earth.

“It’s dangerous outside the house.”

After the divorce, the ex-wife disappeared for four years and unexpectedly gave birth to a pair of twins! Upon reuniting, Third Young Master Shen continuously pressured her into marriage, but the ex-wife's heart was tightly shut. The soft and adorable daughter was worried, saying: “Uncle Shen, why don't you kidnap me and threaten my mom to marry you?” Clearly, she is his biological daughter. The arrogant son, on the other hand, specializes in ruining plans, revealing someone’s embarrassing photos: “If you keep pestering my mom, I’ll send this to the parent group!” He's clearly out to get his dad!

Lou Yao Yao wasted her life fighting over a man, only to find out he wasn’t worth it in the end. Because of this man, she accidentally killed her rival in love, and even ruined the man who had always been watching over her.

Imagine being forced to live, after death, as incorporeal bodies trapped in a vast space of nothingness for thousands of years, with nothing to do but exchanging past memories with other cohabitants (read: weirdos). Everybody wanted out, but there was no way to leave the Void…

Until one day, a young man was finally summoned, as a powerful but reluctant mentor, by a bubbly and motivated but completely naive young girl. Baiyi, finally out of the Void, was the only one who could save all of the other 32 souls from their prison and his summoner might just be The Key to their freedom.

However, Baiyi had to use the techniques and abilities the other souls had taught him throughout the years, and together with his own extensive knowledge of anime and game tropes from his shady and dangerous past as an otaku, to face the biggest challenge of them all: training the clumsy young girl he was forced to partner up with… into a competent sorcerer!

This is a story of heroic adventures, cunning strategies and romantic tales. How will our MC thrive in a world completely strange to him? Where will his ambitions and abilities take him in the palace?

- Description from Novelupdates