I'm Trapped Inside a Prince as the Most Powerful Entity - Chapter 1: The End and the Beginning

Elijah is dying.Afflicted with terminal cancer, his days are limited. So, after deciding to spend his remaining time with family, he boards a plane and sets off for the Pacific Northwest to be with his sister. However, along the way, Earth is transformed by the touch of the World Tree, injecting it with magical Ethera and connecting it to a much larger universe via the System. More importantly for Elijah, though, it also causes his plane to crash, stranding him on a deserted island. But all is not lost, and through the System, he gains the Druid archetype that may be enough to allow him to survive a hostile environment filled with powerful monsters as well as more mundane threats like starvation and the elements. Meanwhile, his sister, Alyssa, must survive the collapse of civilization as she knows it while trying to keep her family safe. Follow them as they try to navigate an apocalyptic world full of game-like stats, classes, and threats aplenty.

It started off peculiarly; first, his domestic cat refused to let him cuddle it.

Lin Qiushi soon found that a sense of disharmony and incongruity began to pervade everything around him.

Then, one odd day, he pushed open a door, and he discovered that the hallway he was familiar with turned into a boundless corridor.

At both ends of this corridor were twelve, identical iron gates.

Thus, the story began.

Ruan Nanzhu said to Lin Qiushi, “When you gaze into the abyss, the abyss also gazes back at you.”

Upon hearing this, Lin Qiushi sank into deep contemplation. He then pulled down the zipper of his trousers and aimed at the abyss…

Ruan Nanzhu: “…Put your pants on properly!”

Super shameless, ill, pampered gong X Shameless, calm shou; a combination of double [or extreme] shamelessness.

- Description from Novelupdates

In this world, orphans or just anyone without any hope for this world can apply to become a “walking target”. Their sole purpose is to be a practicing dummy for the students of the sect who train to become “Demon Hunters”. These students need “walking targets” to test their training on living, walking beings of flesh and blood.
In exchange, they will be provided with food & shelter.
Their existence value is lower than a slave, but if they manage to survive a few years they can receive a life long pension.

Xiao Han is such a “walking target”. One time he witnessed a powerful Demon Hunter disposing a demon. When the demon died, a fragment of the demon that managed to escape entered Xiao Han’s heart. No one saw that, and even Xiao Han himself only felt some discomfort for an instant.

But that thing in his heart soon gave Xiao Han visions, and the first one is of a cultivation method which allows Xiao Han to absorb damage to enhance his body. A perfect cultivation method for a “walking target”.

- Description from Novelupdates

A long time ago, the decayed main god space collapsed and disintegrated, and the wreckage was scattered in parallel universes, giving birth to a new space…

Countless ‘story worlds’ under control have also fallen into the void, regained freedom, runaway out of control, elevated to reality, and turned into reality.

At the same time, these “worlds” are polluted and corroded by the void, giving birth to greater fear and filth…

…

The space of birth feeds on the world.

They compete with each other, their tentacles penetrate through dimensions, invade different time and space, search for the legacy of the main god, drive the apostles to be minions, greedily tearing, seizing, devouring, and reclaiming one world after another, so that they can return to greatness.

…

The innocent eating melon and white waves with the legacy of the Lord God accidentally got involved in the parallel universe “Paradise of Fire” during a cross-border call.

After forcibly binding the demi-human blood, he became an excellent tool man who can repeatedly die, starting the legendary ‘dimension invasion career’.

- Description from novelbuddy