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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Weapon seller in the world of magic

The background story of Wang Zuo is quite straightforward and without any sort of conspiracies. He was the soul of the divine throne of the heavens where the jade emperor sits and rules the entire celestial plane of existence.

For eons, the divine throne went through several repairs and eventually went into a stage where it will cost a great number of resources and time. Hence, the jade emperor was forced to replace it with a new throne.

Obviously, Wang Zuo didn't like to be retired. He protested in rather a violent way, causing mayhem in the heavens and bringing a huge amount of losses of resources to the heavenly palace. As a result, he was expelled from the heavens for eternity.

While wandering all over the universe for about millions of years, he eventually ended up on this earth.

Wang Zuo, the divine throne of the heavens