The answer is 'no'

"Forgive me, my king, but I can't do that?" Zee-Yan-Key answers.

"Why not?"

"The kingdom controls the trade of fire medicine. The Emperor deems that freely distributing the fire medicine is potentially detrimental to His hegemony."

The explanation seems reasonable. After all, if you're in the same position, you would have decided on the same policy. But the answer confirms your earlier suspicion. "So, the Emperor exiles you under the guise of sending you as an envoy in a foreign lands?"

Zee-Yan-Key smiles wanly. "It seems that your wisdom is very much understated, my king. It is as you said."

While countries do send out envoys, sending them to far away countries that have no real diplomatic or political benefits was considered as wasteful. The real reason why Zee-Yan-Key was sent to your country was probably because the Emperor was wary of the former's influence but at the same time didn't want to kill him off unnecessarily, not when he could be used. Having Zee-Yan-Key serve as an emissary , no matter how useless his role is, will show that the man is supporting the Emperor's rule.

So, as long as Zee-Yan-Key doesn't return home, the Emperor will be more willing to let the sleeping dogs lie.

"Is there any other sources?" you ask, not willing to give up.

"There is..."

"Is it nearby?" you press.

"It seems that the basic ingredients can be found here, and I do have the tomes to produce the medicines... but..."

It seems that Zee-Yan-Key's prowess in warfare is unmatched by his ability in diplomacy and negotiation. While he can probably kill you with bare hands easily, you can determine his negotiation intent from far away. You don't really care who are making the weapon, as long as you put them under your control. "If you are willing to serve me, I will make you my purveyor for fire medicine."

"But I swear an oath of allegiance to my Emperor."

"I will never turn my sword against your emperor and will not invade your country, unless your country invades this country."

"It will never happen in a hundred years, not when the distance is too far apart."

"Then you have no problems with serving me, do you? If you want, I can send an official missive to the Emperor to request for his permission. But given your current position with him, that's only for formalities' sake. "

"That will be very much appreciated. I will accept."

Of course he has to accept. Being exiled by Emperor means barely any support will come. In fact, his group has **** but to settle in your country if the situation persists. Your promising not to antagonize his former country, even if symbolic, takes away the hesitance Zee-Yan-Key feels. Plus, having you send that missive suddenly makes his 'diplomatic mission' more legitimate. You don't really care, but as long as he cooperates with you, all is well. If your guess about the potency of such weapons is correct, you might as well send some extravagant gifts to the Emperor as a sign of appreciation. Of course, you're not going to tell him that Zee-Yan-Key will be working for you to recreate the empire's fire medicine but instead serve you as a warrior. You're not lying, since you will call upon him to serve in the military but only in **** emergency.

Both of you call the others inside the room and the discussion of your new arrangement continues well into the evening.