I believe it’s a gun, I would say since a lot of people don’t have access to it that makes whoever has it very powerful. They mainly fight with swords so a gun(especially that powerful) would in many ways be stronger than a sword. It’s really like an object of power, right now the black emperor is so powerful because he is the emperor but also because he seems to be one of the only people with a gun or such a strong gun so he hold so much fear over everyone(also he’s just scary and a little unhinged). The village elder wanted it to study it and most likely to try and make his own at some point or distribute it to other clans. Because if everyone then had access to the gun it would weaken the strength of the emperor to an extent because he wouldn’t hold so much fear.
That’s my opinion on it though! Hope it helped a little :)
The gun. Basically garon(emperor) invented guns. The imae tribe wanted to steal the plans, so planted our mc, our mc had his own goal to poison the Emperor for murdering his mum. He's achieved the goal of poisoning the Emperor amd stealing the plans for the gun but the Emperor wants him for himself anyway, despite his stealing the gun design and trying to kill him.

Can anyone tell me what that jinchenore or whatever it is??? It's hard for me to understand the plot