Mythical Slayer: Mythical Girls Contract - Chapter 1 1 - A Meeting

As the ruler of a munitions empire, Tang Mo unexpectedly fell and was transported to an entirely different world, where he also unexpectedly acquired a “King of Munitions” system.In this underdeveloped world, Tang Mo relied on the abilities granted to him by the system to drive the development of the entire world.After all, the desire for civilization conquest had always been the driving force behind progress, and life had continuously evolved between attack and defense over tens of millions of years...So, selling assault rifles to these archers and training knights to be tank operators... there shouldn't be any problem with that, right? XD

Theatrical regression life of an old-fashioned villain (kkondae) who recalled his past life.

“There’s nothing I wouldn’t do for a better life.”

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Survival in the ‘Otherworld’; a place where only the insane can set foot in.

At 18, Alex Kain is whisked away to Eryndor, a game-like realm where he gains 'Skill Synthesis', a talent to fuse skills into godlike powers. Battling monsters and conquering dungeons, he builds a harem of strong women drawn to his might and charm. With the power to return to Earth bearing incredible resources, Alex faces a growing threat that endangers both worlds in this epic of adventure, romance, and ambition.

Others treated disease to save person, he treated disease to steal heart.

The Frost Goddess was deeply captivated by him. The gentle and kind beautiful teacher was completely enchanted by him. Even the cold and beautiful female assassin melted quietly because of him.

Competing in medical skills? He was the one who treated the Godly Doctor. Competing with backgrounds? Leaders rushed to him. What? You actually wanted to compete with him in a match for match? Looking at the gentle girl beside him, Tang Yu had a headache as he said, “Beautiful girl, how did you fall in love with me?”

- Description from Novelupdates