There's not much info about Kai-Shirr other than he's one of the latest and newest addition on FFXIV characters, starting from the Shadowbringers patch. He's a strapping young man from Mystel race (Miqo'te in Eorzea) with short blue hair who in this cutscene doesn't have but one line, unless you want to add the random pained grunts and stuff that you can see in explainer video.