MTL - Devil’s Son-in-Law - ~ Urgent notice, paused for these days

Crossing the prehistoric times, Chen Changsheng bowed to Tongtianmen and became the most sturdy senior brother of the Intercepting Sect, awakening the reading system.

Read [Holy King], extract the god statue, and automatically upgrade it to the immortal way.

Read [Perfect], extract the self-indulgence method of his transformation, and automatically upgrade it to chaos and self-inflicted law.

Read [Star Change], extract the method of stars, and automatically upgrade Hongmeng Star Change.

…

Just like that, relying on reading from the heavens, Chen Changsheng became the first person to communicate with each other in the past and present.

- Description from novelbuddy

When The Cute Kunoichis Spied on Their Teacher's Secret is a light novel written by Kazuma Kamachi and illustrated by Ryuushi Tajima.

The story takes place in a world where Japan never ended their isolationist phase, and agents from foreign powers are always threatening to steal the country's advanced technology. In order to combat this threat there has been a resurgence of ninjas that use Strategic Martial Arts, techniques that combine cutting-edge modern technology with a traditional foundation of martial arts and ninjutsu. The story follows Souha Sugiyado, a 17-year old ninja instructor and former ninja prodigy who was forced to retire from active duty by the wounds he suffered in his last mission. Souha's four students are all kunoichi who have all gained the rank of Elite Ninja, the highest official rank available to ninja. However, one day two Shogunate ninja approach him with the news that his four students have gone rogue and have stolen a portable modular nuclear reactor, and thus they ask for his help in bringing his students to justice.

Mysterious gates appeared all around the world a few decades ago. Beings emerged from the gates and brought disaster upon humanity. Humanity called them Demon Spirits. It wasn’t until the advent of Demon Suits and Demon Suiters that humans stood a fighting chance.For some perplexing reason, the world’s number one Demon Suiter, Li “God” Xiu abandons his identity to start over again as a newbie trial-taker. He enters the gates to participate in all sorts of trials, in a bid to seek out the reason that enticed his best friend into becoming a trial-taker.These trials weren't the run-of-the-mill dungeons, ranging from game sports (soccer, basketball, baseball, etc) to athletics. Just as fortune favors the brave, what would Li Xiu obtain on his quest?“Are you telling me he’s a greenhorn?” the other trial-takers frustratingly ask while watching Li Xiu's feats that prove why he's the number one Demon Suiter.

Qin Chen crossed into Taiyi Holy Land as a sweeper, and at the age of sixteen awakened the system. As long as he signed in at different places, he could get different rewards.

Sign in at the Land of Emperor Ruins and get the world’s No. 1 Chaos Holy Body and the Chaos Emperor Sutra!

Sign in to seal the magic land and get the quasi-emperor soldiers!

Sign in at the Refining Hall and get the God-level Refining Technique!

Sign in at the medicine garden and get the medicine of immortality!

Sign in at the Imperial Palace and get the Emperor-level forbidden magical power ‘Resurrection from the Dead’!

…

Qin Chen thought that he would just sign in silently until the world was invincible.

One day, the relics of the Great Emperor will appear in the Holy Land, all the holy places, families, and ancient dynasties have come, and there will be an unparalleled demon king in the relics, killing countless powerhouses, ruling the world, and wanting to destroy the Holy Land.

In desperation, Qin Chen could only walk out, slapped the Demon King to death, and sighed: “I just want to be a sweeper and sign in silently. Why do you force me to take action?”

- Description from novelbuddy