Poisonous Snake

In 2200, after a mountain farmer was bitten by an unheard of venomous snake, he was infected with the Dulmen virus and became the first zombie in human history. Since then, the zombie virus has spread from ten to ten, and human settlements have continued to shrink. Those who fight against these zombies are the mecha masters and the armor-makers behind the mecha masters. (Fate update, don't cheat, I love you.) Inspiration comes from dreams.