Lord: Becoming a War Criminal After the Villain's Ruin

(Western Fantasy + Base-Building + Magitech + Conquest + Slow Burn + Multiple Races + Multiple Female Leads + Fake System) Traversed into a game world, becoming the duke's third son, obtained a system, strove toward a world of newfound happiness, only to meet a ruinous end and be exiled to a baron's territory. The dreamed-of happy life was now impossible. After arguing with the system, Lynn made his decision. Can't play galgames, so I'll play war. Lynn: "Industrial Plan, activate!" Years later. Facing the encirclement from various nations, Lynn delivered his speech to his followers: "Do you want total war?"