Metal Mage (Completed Series)

When a 20th-century man is transported to a magical fantasy world, he discovers powerful monsters and evil wizards threaten to kill everyone. He gains earth and metal magic, allowing him to craft armor, swords, and most importantly, guns. As the Metal Mage, he aims to protect the land using his unique abilities and building battle robots.

His journey includes taking over the Order of Mages, constructing railroads to unite kingdoms, and forging trade agreements with dwarves, elves, and even ogres. All while fighting off threats like flame creatures, ice giants, and cave dragons. His ultimate goal is to defeat the mysterious "Master" who lurks in the shadows, manipulating events and building his own army. Along the way, he gathers a harem of powerful women who aid him in his quest and becomes a baron complete with riches and land.