Causal Nexus -

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

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. Causal Nexus

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 world ends in fire," he whispered to his younger self

He emerged decades in the past, in the same Library, before the rot had set in. There, he saw a young version of himself reading by a window. Elias looked down at his hands—they were aged, his hair now a shock of silver. He walked toward the boy, the charred notebook heavy in his hand. But as the engine roared to life, the Library began to burn