Seeing one of the girls bring up some sort of canon, Date could not help but be reminded of some of the Demon King of the Sixth Hell Oda Nobunaga's firearm weapons. However, the fact she stated a comment "You are armed" gave Masamune the impression that she viewed him as some sort of threat. Well, he had no intention of being one, but he was fine with being one if he had to. 

Seeing the girl ask who he was, Masamune turned and gave her a grin. "I'm Oshu's number one, Date Masamune." he said. "I'm not picking a fight here," he said to the girl although he meant for its meaning to be conveyed to the other girl pointing a weapon at him, "But I'm more than willing to take on a fight that I'm being picked for, get it?"