Portraits revealed through your current reading position.
A different kind of residual than Agatha, who clearly hated whatever the Eulogist is.
When Carl tried to reconstruct where he'd heard the term "The Eulogist" before, Paulie was one of the threads. Carl had first heard it in conjunction with a nebular religious cult, then again as Agatha's boss or something like it. Paulie is a different kind of residual than Agatha, and he clearly hated the Eulogist — Carl couldn't even settle on what to call it.
A person? A monster? A Mar?
Zev would shortly answer that it is another name for the AI in the Center System.
A residual whose hatred of the Eulogist is one of Carl's few clues to what it is.
Also appears in books you've already read — spoiler-safe to their endings: