WW1 French trench raider, 1915

These soldiers would sneak out of their own trenches at night, often covering themselves in burn cork to darken their uniforms and exposed skin, silently creeping towards the enemy trench so that they could slit the throats or bash in the heads of the enemy whilst they slept. They would wreak havoc throughout the enemy position, using knives and clubs to maintain minimal noise, and carrying grenades which they would throw into sleeping quarters when they left. The fear factor of that no one could sleep safe, knowing that the enemy sent men like this.