Nexus | Causal

He didn't have a choice. To ensure he grew up to build the machine that would bring him here, he had to give the boy the book. He had to be the spark that started the fire.

The concept is widely explored in fiction and philosophy as a way to understand our interconnected reality. Causal Nexus

Elias stood in the ruins of the Great Library, clutching a charred leather notebook. He was a "Time-Sensitive," capable of feeling the hum of a —a point where time tracks diverged and collided. He didn't have a choice