Mutant Apocalypse, I Have an Invincible Mechanical Fortress — Episode 6

Human weapon Lee Han awakens the "Apocalypse Bunker System" in a ruined world. Starting with only a welder and a modified harvester, he builds a mechanical farm on Sunset Hill. While humanity struggles against zombie hordes and famine, Lee Han enjoys hotpot in a bulletproof greenhouse, grows anti-toxic wheat, and stockpiles food. By building high walls and recruiting superpowered individuals, he upgrades his farm into an impregnable steel fortress equipped with heavy artillery and Titan mechs.