MTL - Immortal Emperor: Reborn in the Mixed City - Chapter 16 Back to school

The end of the world is coming, the world has undergone great changes, and everything has changed. Plants, animals, and even insects, as long as there are living things, have mutated.
Become more powerful, and even evolved supernatural abilities, such as chickens and ducks that can fly to the sky, such as cats and dogs that can breathe fire.
But only humans, without any obvious changes, seem to have fallen from the top of the food chain to the bottom of the food chain overnight.
Any creature that can open its mouth to eat can treat humans as food.
But fortunately, this world has not completely killed humans. Gradually, humans discovered that they had the ability to cultivate compatibility with other creatures.
As long as it has a high degree of compatibility with some powerful mutant creatures, it can be used for its own use to achieve the purpose of protecting itself.
Fang He is a person who is very compatible with mutant animals, but it is also because of his ability that he has changed from the strongest to the stupidest.
Fang He, who was reborn, said, “Hmph, this time…”

- Description from novelbuddy

An incredibly athletic older brother, Tenryu Taiga. A programming genius girl, Tenryu Fuyuki. The two siblings separated for eight years ended up living under one roof again after facing the problem – a lack of funds for living expenses.

Fuyuki proposes a way to earn money, a core system deeply involved in people’s daily lives, a game that awards you money as a prize for defeating malicious bugs in cyber world, the 《Aries》structure. Taiga after becoming a warrior in the game relying on his inborn senses, is puzzled by the unfamiliar sensation.

One day Saionji Rui, Fuyuki’s best friend appears and is attacked by a mysterious bug― “I’ll be waiting, my prince.”. Hybrid fantasy battle of cheating siblings begins here!

Outer Sect Disciple Chen Yu, assimilates within his body a fiendgod heart.

The heart, is the backbone of life, the human body’s fatal vital point. And it can be said that Chen Yu’s heart is actually his strongest defense point, and permits him to overtake demonic beasts, or divine beasts unlimited potential.

Henceforth, he steps onto the stage and surges forth on a magnificent scale, in a heart-rending mysterious journey.

Talented as a cloud, an unparalleled supreme talent.

10,000 races glorious, cross boundary battles.

Only my heart, eternal!

- Description from Novelupdates

In this world, Planet Earth had undergone great changes and humanity is faced with extreme danger. Luckily, humans have something called the Heaven Dao software.