She's the "secretary from hell" who hates her job and finds perverse joy in making everyone within a two-mile radius suffer.
She's the technical writer in Dilbert's engineering department. Tina believes any conversation within hearing distance is intended as an insult to her profession and her gender. She strives to maintain her dignity while surrounded by engineers who don't have a proper respect for her work.
Mordac - He's the evil-hearted director of Information Services for Dilbert's company. He believes his mission is to make it as difficult as possible for employees to use their computers or the network.
When I need a new character to play a bit part, it often ends up looking like the same guy. Privately I call him "Ted, the generic guy," even though he sometimes has other aliases in the cartoon.
Phil, The Prince of Insufficient Light, is the ruler of Heck (for sinners whose transgressions aren't serious enough for Hell). He pops up about once a year to impose mild sanctions for mild sins. For example, once he punished Dilbert by making him eat lunch with the accountants.
Dilbert © 2005, United Feature Syndicate, Inc.