It most definitely will be about charm considering his bloodline.Iruma: "I'm a human..."
Azz & Clara: "Awesome, explains a lot, how do we sign up to be your familiars, too?"
That being said, we know that Azz hasn't revealed his bloodline ability yet, and a big group stand-off with Iruma on the line would be a great time to reveal it...especially if it has something to do with charm or deception.
Clara would be on board immediately , Azz might take a bit to process everything but still take Iruma’s side. (Please do, this’ll hurt otherwise)