The Heroine is My Stepsister, and I'm her Final Boss - Chapter 60: Let there be War.

After dying as a college student, Kain wakes up in a magical world where people form bonds with spiritual creatures to fight alongside them. Determined to rise to the top, he relies on a System and loyal companions.Everything seems to align with his ambitions—except the spiritual creatures he can contract seem to be remarkably…strange

The amiable looking patriarch is gazing at a stone monkey: “Wukong, what do you want to learn from me?” “It’s all up to master’s instruction.” The stone monkey respectfully replied: “As long as I will be able to beat up Tathagata, then it’s alright.” One hundred years later, the stone monkey defeated Tathagata and ascended the throne, becoming the Jade Emperor.

- Description from rhadoko

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.

One day, I was summoned to this world.