Jack is an English vagabond turned soldier of fortune turned adventurer. He is highly intelligent (though uneducated), and has extraordinarily poor impulse control. The latter leads to many situations that only Jack Shaftoe could find himself in, e.g., chasing an ostrich into a Turkish harem during the Battle of Vienna. This poor impulse control, Jack claims, stems from the influence of an Imp of the Perverse which compels him to do things against his, or most anyone's, better judgment. Jack's sanity is, consequently, often called into question by his companions. He also apparently supplies his own heroic narration of his exploits as he performs them.
