An Inquisitor can't do everything by themselves, and sometimes the things they need others to do are particularly unsavory. Enter the demonic, the dangerous, and the downright dastardly.
To be honest, though, I can't reminder all of their backstories, so it's possible that Slick isn't dastardly at all, but I'm sure Churabael is considerably daemonic, and that Damien 1427 is completely dangerous!
Churabael, Bound Daemonhost
Damien 1427, Arco-Flagellant
Slick Devlan, Gunslinger