Why did thorin demand to be taken to the master of the men of the lake?

Thorin Oakenshield demanded to be taken to the Master of the Lake-men because he sought assistance and support for his quest to reclaim the Lonely Mountain and its treasure from Smaug the dragon. He believed forming an alliance with the Lake-men, who had helped the dwarves previously, would be beneficial for both parties. Additionally, Thorin wanted to assert his claim and establish his authority as the rightful king under the mountain. This meeting was crucial for securing resources and gaining allies in the face of the challenges ahead.