Tang Shaoyang thought it was something important for them to summon him. He guessed that might be related to the Void Cult or something, but they called him just for a complaint from the Hurakan Kingdom.
The way Clementine and Arion addressed the issue, it was not the King of the Hurakan Kingdom that issued the complaint. They didn't mention the King once in the conversation to pressure him. They just brought out the kingdom name to his face.
He was initially beyond annoyed that some random people tried to interfere with his class. However, he got valuable information as well from that conversation. The fact that there was limited information about his class.
Even though the Nirvana Alliance has been hunting the people with the Spirit Contractor class. It seemed people didn't put much interest in the class because there was not much information about the class out there.
