My starting summon is a small skeleton - Chapter 274 - 271 Rescued (Seeking Subscriptions)

Calamity descends upon a a tranquil world in the black of night, transforming it into a death game! This a a true apocalypse, but this is not the end of humanity!

- Description from Novelupdates

To correct the mistakes of his past, a young man is forced to narrow the space between science and witchcraft, as he ventures on a quest to save his world from complete destruction.

A lifetime ago, Chu Xun was shackled and thrown in jail on false charges. For three whole years, he suffered extraodinary torment from his cellmates every day. Even though he had escaped death many times, he still died from his cellmates’ fists the day before he was to be released.

After death, Chu Xun transmigrated to a different world of cultivation, where cultivation was the one true path. Carrying the weight of his hatred, Chu Xun began to cultivate in hopes of becoming an Immortal Emperor, who could manipulate heaven and earth and travel through time. After painstaking cultivation of three thousand years, he succeeded. Then he sacrificed all his cultivation without hesitation and returned to the day before he was to be released.

This life, he wanted to find out the truth and the one behind his murder in last life. He would continue to cultivate and strengthen himself so that the tragedy would not repeat itself. He wanted to master his own destiny.

In this life, what people would Chu Xun encounter and what experience of love and hate would he have with them? What difficulties would he encounter and how would he overcome? The answer is the book.

- Description from Novelupdates

A seemingly ordinary training exercise led Chen Jian and his squad into a completely different time and space.In the post-apocalyptic world, monsters run rampant, and the surviving humans struggle to live under their terrifying claws.To fight the monsters, the living have abandoned everything.Human nature no longer exists; beastliness is the mainstream.To defeat them, one must first become them.-----------------Chen Jian was supposed to be like the others here, pursuing the maddening evolution.But, when the tungsten-core armor-piercing round first penetrated the Kui Niu's keratin armor, he suddenly discovered...Perhaps there is another way to stay alive?