Dilbert's "sanitation engineer" is a mysterious character who has inexplicable knowledge of all subjects from science to philosophy. He shows up occasionally to solve impossibly complex problems for Dilbert or Dogbert.
His role has diminished somewhat in recent years but he'll be back.
She gives us an idea where Dilbert got his skill with technology. On the outside she's a cookie-baking, fifties sort of woman. But she reveals in small glimpses an incredible depth of technical skill and understanding.
Dilbert's father has never been seen in the strip, only referred to. He's been at the all-you-can-eat restaurant in the local mall for years. He won't leave until it's "all he can eat."
One day Dilbert determined that it was impossible for all dinosaurs to be extinct. Lo and behold, Bob the Dinosaur appeared from behind the couch.
Bob is dumb, cheerful and follows Dogbert's commands without question. Dinosaurs may no longer rule the Earth but Bob is the king of the wedgies.
Bob has a mate -- Dawn, and a son -- Rex. Dawn and Rex still live in Dilbert's house, but as with most living dinosaurs, they prefer to hide behind the furniture when people are around.
The Elbonians hail from Elbonia, a small mud-covered fourth-world country that both Dilbert and Dogbert have visited for various reasons. I use it whenever I need a country that is "foreign" to all Dilbert readers.