Lance Priest is an agent with the CIA.
According to a blurb on the first recorded adventure, he was a college student, and part-time used car salesman, who came to the attention of the Agency because he was "also a liar, a chameleon, a different person to everyone who meets him". "He lived for moments when he was challenged to create characters and build backstories, traits, wants, needs and desires. Lance was a born liar. Leopards have spots. Fish swim. Lance Priest lies."
The interesting thing about many liars is they cannot tell when they are themselves being deceived. That is most definitely NOT the case with Priest. While lies are second nature to him, recognizing a lie is almost like breathing.
Like when someone is pretending to be someone else. Priest explains that "People aren't born with names. They are given them. They become them. A Jim is named James at birth but ends up a Jim. Michael stays Michael instead of becoming Mike. Elizabeth becomes Lisa or Liz. Either way, you become that name. It's who you are. You carry it with you, wear it. When people like about their name it is easy to tell. It doesn't fit."
"Truth be told, and it wasn't often told by Lance Priest, he'd fibbed and lied and B.S.'d his way through most of his 21 years. A half-day of whoppers and white lies told to others during the Foreign Service Officer oral assessments was nothing. It was at one of these assessments that the interviewer pulled a gun out from somewhere Priest did not see, put it on the table, and then informed the surprised young man that he would "be of no use to your country or anyone for that matter unless you can survive the next 72 hours". Priest might have written it all off as a bizarre prank except for the gun - and the silly grin on the man's face that told Priest the man was keeping a secret. It was one interesting way of being considered for a job not for the Foreign Service but for the CIA.
Training would prove a challenge but when he is put out into the field, he shows just how good his adaptability is and with that, his usefulness.
And then you throw in a lady who will become very close and important to Priest, aka the Preacher, Marta, "a rogue KGB operative who kills almost everyone she meets".
"Sometimes songs just start playing in his brain at the most inopportune times."