The Daimyō did have a trump card, but Uchiha Yi was a real problem. He knew the Flying Thunder God Technique, and the Daimyō knew what that meant. Tobirama Senju had used it to become the fastest man in the Shinobi World.
Many powerful Ninja had died to the Flying Thunder God Technique.
And Uchiha Yi had mastered it too. That made him difficult to deal with.
Why had those people in Konoha taught the Flying Thunder God Technique to those inherently wicked members of the Uchiha Clan?
Even without that technique, Uchiha Yi was a terrifying Ninja. By all accounts, he already rivaled Madara Uchiha at his peak.
The Daimyō was no fool. He knew the legends of Madara Uchiha, a man who had stood as Hashirama Senju's equal.
If not for Hashirama Senju, Madara Uchiha might have tried to unite the entire Shinobi World himself.
And where would that have left me? Luckily, Hashirama Senju had stopped Madara Uchiha. Otherwise, the Daimyō would have had to beg those people to intervene again.
Getting those people to act was no easy matter.
Even the Daimyō himself did not know who they were or why they helped the Daimyō, though the Daimyō had to do certain things for them in return.
But Uchiha Yi was already among the strongest in the Shinobi World. With the Flying Thunder God Technique on top of that, he could fight or leave whenever he pleased. So however humiliated and uncomfortable the Daimyō felt, he still had to pay Uchiha Yi.
As for dealing with Uchiha Yi, that depended on whether an opportunity arose later. First, the Daimyō had to tell those people about him.
Hiruzen Sarutobi was delighted that the Daimyō had delivered an entire year's worth of war supplies in one go.