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

Mark's spirit entered his factory space and the assistant robots proceeded with assembling all the parts.

This time, the Robotic Cerberus was connected to a large external battery, which was fully powered.

The whole thing was brought to the testing space and Mark proceeded with the launch.

Mark land on its back to activate it. Just as he was about to switch it on, Mark took back his hand in nervousness.

Mark remembered Allen's advice and wondered if he could integrate Alina's core into this robot by himself.

But, he doesn't want to risk getting it damaged either.

"System, can the core get damaged if something unexpected happens in this project?"

The system was always quick to reply.

*Ding! Negative. The exterior of the core is made from adamantium alloy, which can resist the attack of even a demigod.

Return of Alina