The Demon Queen's Contract - Chapter 99: She’s like a phantom

Unlimited opening, unlimited power! The mutated mobile phone has a magical app download! All kinds of buildings, can rise to the sky, can sneak into the sea, can be hidden… hidden secrets of the big!

Tang Zhen’s ability to build a city is… Building a city, playing with explosives, crushing the ground and grabbing the ground.

Tang Zhenduan sits on the top of the mountain, and at his feet is an endless floating city, guarded by dragons, surrounded by angels, and countless giant guns stand in the sky!

In the depths of the ocean a million miles ahead, it is another big 6-level building that is waiting for his conquest!

- Description from MTLNovel

A fighting genius.

Volume 1 (Set between volumes 13 and 14)

A series of short stories set before the events of volume fourteen including how Team GROUP was formed.

Volume 2 (Set between volumes 16 and 17)

A series of short stories including two separate meetings between Touma’s and Mikoto’s parents, two tales involving two of the Level 5s of Academy City, and other funny stories involving some of the characters.

Beings that create and control monsters and demons, beings that build and reign over malicious labyrinths, the chosen individuals to possess an overwhelming Unique Skill… They are the Demon Lords.