Using smile Venemously for Kiryu's agent style is brilliant, considering that it was originally used in yakuza 4 in fights where Kiryu was mainly recognized as just an overly burly thug instead of who he truly is, the Dragon of Dojima. So it makes sense that the same sense of "you know this man is bad news, even if you don't recognize him" would also occur when he went undercover as Agent Joryu.
What a thing to wake up to while I prepare for work. I didn't expect that you'd also make for Agent, but it was pretty obvious now that I think about it.
WE'RE SMILING VENOMOUSLY WITH THIS ONE! KEEP COOKING!