Snowstar

Mark is a genius military weapon designer who was kidnapped by a mafia gang after refusing to work for them.
They forced him to design unique weapons for five years, until one day he successfully escaped only to get shot by his trusted comrades.
*Ding! You awakened a weapon system.
When he opened his eyes, he was in a different body and in a different world.
"You want to kill a wild boar without being detected? Forget about bow and arrow. Here, I present you this sniper rifle."
"You want to kill a horde of goblins from the sky? Forget about those flying carpets and brooms. Here, I present you the fighter jet." 
"You want to kill a dragon? Forget about taking the help of the S-class adventure team. Here, I present you a nuclear bomb."
Join Mark Spencer/ Lu Zhen as he brings the whole world to its knees with the help of his weapon system.
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Note: Author isn't born in an English-speaking nation and has no editor either. So, please be understanding if there are any grammatical errors.
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Author's current works: War Online, My Soul card is a Reaper
Author's other notable works:  The Last Slytherin, The Sharingan Hyuga
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You can also support the Author through Patreon

https://www.patreon.com/snowstar

Weapon seller in the world of magic

Northern Yuan Province, Silla town;

In the most famous brothel of the Silla town, beautiful maidens were dancing as the top courtesan was playing a piece of melody music, good enough to make everyone go into a trance and enjoy it.

There are many men around but two of them seemed set apart from the others. No one seemed as wealthy as two men whether it was their attire or the dishes and the wine they were served. They were also accompanied by three popular courtesans.

One of them was actually the crown prince who was on the run while the other was the lord of the town. As no one had ever seen the former crown prince before, he was wearing a half-mask that was covering the left part of his face, not to mention he was in the 6-circle realm, and was sitting up on the second floor reserved for only VIPs, they only assumed that it was some powerful elite warrior their town lord knew.

An offer to the former crown prince