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

The lava golem is more than 3000 meters big with no legs to move around. One can say that is a half-golem, considering its base is its abdomen. It is like the entire Mt. Jizu had grown arms, and head, and came into life.

To talk more about its appearance, it has six eyes with three eyes on each side placed vertically on top of each other. Each eye is about 30-40 meters big in size, enough to terrify people with one glance.

On its forehead, there is a brightly glowing gem, the size of a 30-story building (~120m).

There's another glowing gem, located in the middle of its chest and this one is the size of a 120-story building (~500m).

As one would believe, both of them turned out to be fire seeds. Sensing its cultivation from far away, Lan Ju opinioned that it is at the peak stage of the 9-circle realm but its strength would be far higher. If compared to the beasts, the lava golem would be a beast emperor.

Battle for the seed of fire (part-1)