[Western Crossover] A Wanderer in the Batcave

This story has been abandoned. I can't keep writing it, so please don't start reading. Berg Bennett is a newly enlisted soldier. While on night watch, he encounters an enemy ambush. After raising the alarm, he joins the battle. The battle ends in defeat, and the other soldiers die. He too is listed as an ordinary soldier killed by the enemy. This young man, with few personal connections, is mourned by only Steve and Bucky, who have yet to receive the serum. But in truth, an unknown creature has possessed him, hoping to take over his body and use it to commit slaughter. Unfortunately for the creature, though Berg is an ordinary man, he has one quality that sets him apart: an iron will. The powerful evil being thought escaping its seal would be easy, but Berg traps it inside his own body and binds it in turn. In that backward era, he knows no one can kill it. Perhaps this is one of those moments when even a tiny, ordinary person can be great. He chooses to die with it, struggling amid the chaos, its whispers, and the crushing madness as he searches for death. He stays away from people, searching for death alone so that, should he lose control, he won't put a crowd in danger. He wanders through all kinds of perilous places. He keeps the creature trapped, and the energy left behind transforms him. He no longer fears death or feels hunger. He wanders on, keeping it imprisoned for more than seventy years, until he reaches the age of superheroes. Batman disappears for a little while every so often. The third Robin notices, and under Batman's guidance, the Robins discover a soldier worthy of their admiration, sleeping deep in the Batcave. The protagonist is a native of this world and knows nothing about the story. Before enlisting, he was a good friend of Skinny Steve. His CP is Batman. Theme: I want to write a story with a more serious tone