Nexus: Causal

"The world ends in fire," he whispered to his younger self. "Unless you build the Machine." Perspectives on 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. Causal Nexus

“Wally learns the hard way that good intentions don't off set the consequence of time travel... Wally's actions have already set off a chain of events that can't be stopped.” Fanfiction.net "The world ends in fire," he whispered to his younger self

“The causal nexus divided when Nyssa changed history... causing the universe to exist in two quantum states and releasing blinovitch energy.” Tardis | Fandom “Wally learns the hard way that good intentions

Elias spent his life following the equations in the notebook. He built the Chronos Engine, a device capable of piercing the veil of the multiverse. But as the engine roared to life, the Library began to burn. The friction of the time-fissure ignited the ancient scrolls.

In a panic, Elias realized the "fire" the man spoke of was the very act of building the machine. He grabbed the notebook and stepped through the shimmering portal.

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.