Sigma appeared in this world due to the fact that he was inscribed in the Book. All around him was a desert filled with emptiness. His only possessions were the clothes on his back and a train ticket from a non-existent station. He also had to come up with his own name, so he called himself Sigma.
While Sigma was wandering the desert, he was captured by an armed group and held captive, where he eventually discovered his ability, forcing his captors to use his ability for the sake of for their own benefit.
Still, Sigma was able to escape from there, and continued to wander the world nihilistically due to the fact that he did not know why he lived or existed.
At some point, Sigma met Fyodor. They met under some abandoned shed. He didn't know him, so he was scared because he thought that he would try to harm him.
"..."
Sigma quickly looked back, wanting to run away. He didn't have much strength and energy since he hadn't eaten or drunk for a very long time, and his body was physically weak because of this, but he wanted to get away from it as soon as possible.